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Mast cells are commonly found in pancreatic ductal adenocarcinoma (PDAC), yet their role in the disease remains uncertain. Although mast cells have been associated with depression in several diseases, their connection to PDAC in this context remains unclear. This study explored the correlation between mast cells and psychosocial stress in patients with PDAC. Prior to surgery, 40 patients with PDAC (n = 29 primary resected, n = 11 neoadjuvant treated) completed four questionnaires assessing stress and quality of life. Immunostaining was performed on the resected tumor tissue. Spearman analysis was employed to correlate mast cells with distress and neuropeptides serotonin and beta-endorphin serum and tissue levels. Patients with PDAC exhibited elevated levels of distress and worry. Lower number of mast cells within the tumor correlated with greater psychological burden. Among primary resected patients, mast cell count moderately correlated with joy and inversely with worries. Following neoadjuvant chemotherapy, strong inverse correlation was observed between anxiety, depression, and mast cell quantity. No correlation was found between mast cells and serotonin or beta-endorphin levels. In summary, mast cell presence inversely correlates with psychosocial stress, suggesting a link between immune cells and psychological well-being in pancreatic cancer. Targeting mast cells might offer therapeutic avenues for addressing cancer-induced depression and anxiety. [ABSTRACT FROM AUTHOR]

A 10-y-old spayed female Staffordshire Terrier dog was evaluated because of a cutaneous left ear base mass. Cytology revealed sheets of cells with anisocytosis and anisokaryosis, round-to-oval or plasmacytoid cytoplasm, and round, central, or eccentric nuclei; binucleate cells were present. Cytologic findings were consistent with a round cell tumor (plasmacytoma or agranular mast cell tumor), amelanotic melanoma, or anaplastic carcinoma. Histologically, neoplastic cells were polygonal to elongate, with round-to-oval nuclei and prominent nucleoli and arranged in sheets and nests on a fibrovascular stroma. Neoplastic cells with plasmacytoid morphology (round, glassy, eosinophilic cytoplasm with eccentric nuclei) were present in ~30% of the neoplasm. There were 18 mitoses in 2.37 mm2 (10 FN22/40× fields). Neoplastic cells had cytoplasmic immunolabeling for melan A and PNL2 and no immunolabeling for AE3/1 and MUM1, consistent with a dermal melanoma with plasmacytoid differentiation. The patient was re-evaluated ~1 mo after the first biopsy because of local recurrence of the original mass and new masses on the interscapular area and right elbow; these neoplasms were histologically identical to the original submission, plus scattered neoplastic cells in the new masses contained brown cytoplasmic pigment. The dog was euthanized because of swelling and hemorrhage of the tumors and right pelvic limb lameness. Our findings were consistent with a dermal melanoma with plasmacytoid features that were similar to human plasmacytoid melanoma, a rare variant of human melanoma that is diagnostically challenging as it may mimic a plasmacytoma. [ABSTRACT FROM AUTHOR]

Cutaneous and subcutaneous mast cell tumors (MCTs) are common canine neoplasms characterized by variable biological behavior. Tumor-associated macrophages (TAMs) and tumor-infiltrating lymphocytes (TILs) can be effective prognostic markers in numerous human neoplasms and are increasingly investigated in dogs. The aim of this study was to characterize immune cells in canine MCTs and their relationship with histological location (cutaneous, subcutaneous) and histologic nodal metastatic status (HN0-3). Thirty-eight MCTs (26 cutaneous, 12 subcutaneous) from 33 dogs with known sentinel lymph node (SLN) metastatic status were immunolabeled for Iba1 (macrophages), CD20 (B cells), CD3 (T cells), and Foxp3 (regulatory T cells). Semiquantitative scoring of interstitial and perivascular CD3+, CD20+, and Foxp3+ cells and morphological evaluation of Iba1+ cells were performed. For each marker, the percent immunopositive area was evaluated by image analysis. All MCTs were diffusely infiltrated by Iba1+ cells and variably infiltrated by CD20+, CD3+, and rare Foxp3+ cells. Stellate/spindle Iba1+ cells were associated with HN2 and HN3 SLNs. Perivascular Foxp3+ cells, CD3+ cells, and percent CD3+ areas were increased in subcutaneous MCTs. Interstitial CD3+ cells were increased in cutaneous MCTs with HN0 SLNs. No differences in CD20+ cells were identified between cutaneous and subcutaneous MCTs and among SLN classes. MCTs were markedly infiltrated by TAMs and variably infiltrated by TILs. Stellate/spindle morphology of TAMs associated with HN2 and HN3 SLNs is suggestive of a pro-tumoral (M2) phenotype. Cutaneous and subcutaneous MCTs have different tumor-immune microenvironments, and T-cell infiltration might contribute to prevention of nodal metastatic spread of cutaneous MCTs. [ABSTRACT FROM AUTHOR]

Histologic grading of canine cutaneous mast cell tumors (cMCTs) has prognostic and therapeutic implications, yet validation for subcutaneous MCTs (scMCTs) is lacking. For scMCTs with or without dermal invasion, determining their biological behavior remains poorly standardized and sometimes sparks controversy. This prospective study aimed to assess the prognostic utility of the 2-tier histologic grading system in MCTs with different growth models (GMs) and explore the prognostic impact of the GM itself. We assessed 6 histologic GM categories: solely cMCT (C-SC0), cMCT with superficial (C-SC1) or deep subcutaneous (C-SC2) involvement, solely scMCT (SC-C0), and scMCT with deep (SC-C1) or superficial (SC-C2) infiltration of the dermis. Ninety-one MCTs from 76 dogs undergoing excision and regional/sentinel lymphadenectomy were examined. GM classification identified 11 (12%) C-SC0 tumors, 12 (13%) C-SC1, 15 (16%) C-SC2, 21 (23%) SC-C0, 15 (16%) SC-C1, and 17 (19%) SC-C2. Mitotic count, 2-tier grade, nodal involvement, surgical margins, and outcome were stratified according to GM. scMCTs lacking dermal invasion, historically associated with a benign clinical course, had a poor prognosis in 10% of cases. cMCTs exhibiting deep subcutaneous involvement included the largest percentage of high-grade tumors (33%), had the highest occurrence of overt nodal metastases (33%), and had the lowest 1-year survival rate (86%). Histologic grade was confirmed as a relevant prognostic factor, surpassing nodal involvement and histologic margin status. The 2-tier histologic grading enabled the identification of all MCTs with aggressive biological behavior, regardless of their cutaneous or subcutaneous location. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer is becoming a bigger health issue for cats, much like it is for humans. However, most research has focused on dogs, leaving a gap in our understanding of how cancer affects cats, especially in countries like Korea. In this study, we looked at ten years of data on cats diagnosed with tumors in Korea, aiming to find out which factors—like age, breed, or where the tumor is located—might increase the risk of the cancer being serious or malignant. We discovered that older cats were much more likely to have aggressive cancers, especially in areas like the mammary glands and digestive system. On the other hand, some types of cancer, like squamous cell carcinoma (a type of skin cancer), were much less common in Korea than in other countries. These findings can help veterinarians better understand which cats are at higher risk and encourage early diagnosis and treatment. This research adds to what we know about feline cancer and helps improve the care we provide for cats around the world. Feline cancer is increasingly recognized as a major cause of mortality, yet data on tumor prevalence and behavior in cats, particularly in non-Western regions, remain limited. This study analyzed a decade of feline tumor data in Korea from 2012 to 2022, focusing on age, breed, and anatomical location as predictors of malignancy. Data were collected from 683 cats, with regression analysis applied to determine significant associations. Older cats exhibited a markedly higher risk of malignancy, particularly in mast cell and mammary tumors. Tumors in the mammary gland and alimentary tract had malignancy rates exceeding 90%, underscoring the need for early detection in these regions. Interestingly, squamous cell carcinoma was rare in the skin, in stark contrast to Western studies, likely reflecting differences in environmental exposure. While breed was not a statistically significant predictor, certain breeds, including Persians and Russian Blues, showed a higher frequency of malignancy. These findings highlight the importance of regional tumor research in cats and the need for larger, multicenter datasets that incorporate environmental, genetic, and lifestyle factors. Understanding these influences will help refine veterinary care and improve cancer treatment outcomes in feline populations. [ABSTRACT FROM AUTHOR]

Simple Summary: Cutaneous mast cell tumors (cMCTs) are a common type of tumor in dogs. This study measured blood concentrations of endocannabinoids, namely 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA), and AEA congeners, namely N-palmitoylethanolamine (PEA) and N-oleoylethanolamine (OEA), in 17 dogs with cMCTs and 11 healthy dogs. Dogs with cutaneous mast cell tumors had significantly higher levels of 2-AG and lower levels of AEA and PEA compared to healthy dogs, while OEA levels showed no difference. The ability of these endocannabinoids to serve as differentiators between healthy dogs and those with tumors was evaluated, and 2-AG was found to be a highly accurate (98%) indicator for identifying dogs with cMCTs. Levels of 2-AG above 52.75 pmol/mL had 94% sensitivity and 90% specificity in detecting the tumor. This is the first study to show that endocannabinoid levels are altered in dogs with mast cell tumors, indicating their potential use as biomarkers for diagnosing or monitoring this type of cancer in the future. A cutaneous mast cell tumor (cMCT) is among the most common tumors in dogs. Endocannabinoids (eCBs) belong to the endocannabinoid system (ECS), which involves also cannabinoid receptors and an enzymatic system of biosynthesis and degradation. In this study, plasma levels of N-arachidonoylethanolamine (AEA), 2-arachidonoylglycerol (2-AG), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA) were evaluated in 17 dogs with MCTs of varying histological grades and clinical stages, as well as in a control group of 11 dogs. Dogs affected by cMCT had higher plasma levels of 2-AG (p = 0.0001) and lower levels of AEA (p = 0.0012) and PEA (p = 0.0075) compared to the control group, while no differences were observed at the OEA level between healthy and cMCT dogs (p = 0.9264). The ability of eCBs to help discriminate between healthy and cMCT dogs was interrogated through the area under the ROC curve (AUC). An accuracy of 0.98 (95% confidence interval [CI], 0.94–1.02) was found for 2-AG, of 0.85 (95% CI, 0.71–0.99) for AEA, and of 0.81% for PEA (95% CI, 0.64–0.69). Values > 52.75 pmol/mL for 2-AG showed 94% sensitivity and 90% specificity in distinguishing cMCT. This is the first study to demonstrate alterations in plasmatic levels of eCBs in dogs affected by MCTs, suggesting the significance of these biomarkers in the tumorigenic process and their potential use as biomarkers in the future. [ABSTRACT FROM AUTHOR]

Background: Mast cell tumors (MCTs) are the most common malignant skin neoplasms in dogs. In the past, the distinction between cutaneous MCTs (cMCTs), originating from the dermis, and subcutaneous MCTs (scMCTs), originating from the subcutaneous tissue, was not made. Histopathological differentiation, including grading, is important for prognosis. However, the Patnaik and Kiupel grading systems were proposed for cMCTs only. The objective of our study was to describe and compare the signalment of dogs with scMCTs and cMCTs and histopathological features, anticipating similarities in both groups. Data of dogs histologically diagnosed with scMCTs or cMCTs between September 2020 and July 2023 were analyzed retrospectively. Signalment, tumor location, histopathological features, completeness of removal and lymph node status were recorded. Results: Data on 305 scMCTs and 1291 cMCTs were collected. Breed distribution was different between scMCTs and cMCTs (P < 0.0001). Mitotic count (MC) was not different between scMCTs (1.63) and cMCTs (1.58) (P = 0.8490). Compared to cMCTs, scMCTs more often had anisokaryosis, bizarre nuclei and multinucleation. Kiupel high grade was more often assigned to scMCTs (51/292, 17.5%) than cMCTs (154/1291, 11.9%) (P = 0.009). The odds of MCTs being assigned a high grade in scMCT was 1.578 higher than in cMCTs (95% confidence interval [1.116–2.232]). Conclusions: Histopathological differences between scMCTs and cMCTs were observed. A Kiupel high grade was more often assigned to scMCTs than cMCTs. Whether these histopathological findings correlate with clinical outcome has to be established in additional studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Canine mast cell tumors (MCTs) are a neoplasm frequently diagnosed in dogs that have a very variable aggressive behavior. The aim of our research was to assess the potential role of KIT in canine mast cell tumors in term of response to therapy by investigating the association between KIT expression patterns, the cumulative survival and the progression-free survival in dogs treated with tyrosine kinase inhibitors postoperatively. Dogs that underwent surgery alone were used as a control population. A log-rank test was used to check the differences between the curves, showing that tumors with KIT staining pattern 3 were significantly associated with decreased CS compared to tumors with KIT patterns 2 and 1. Our data suggest that the anomalous expression of KIT is negatively associated with the efficacy of tyrosine kinase inhibitors, thus providing a meaningful prognostic information about the treatment outcome. Several reports have indicated that canine MCTs express a mutated form of a tyrosine kinase receptor, namely KIT, that is involved in abnormal mast cell growth and differentiation. Currently, the post-surgical prognosis for MCTs is related to three different KIT immunohistochemical expression patterns. However, to our knowledge, there are few studies specifically exploring the efficacy of treatment with tyrosine kinase inhibitors related to KIT staining pattern. The purpose of this study was to investigate the potential theragnostic role of KIT expression patterns by studying their correlation to the overall survival and progression-free survival in dogs treated with only tyrosine kinase inhibitors immediately after surgery. We selected 66 cases of canine cutaneous MCTs with complete clinical background. A statistical analysis was performed to assess the overall survival status. Our data suggest an important role of KIT in the etiopathogenesis of canine MCTs and indicate that the anomalous cytoplasmatic distribution of KIT is potentially related to a lower efficacy of tyrosine kinase inhibitors, thus providing a significant prognostic information about the treatment outcome. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer is the leading cause of death in adult dogs. All dogs would benefit from early diagnosis, but there are no official guidelines for cancer screening in pets, although many different diagnostic tools for cancer detection are being studied. With our analysis of 14,636 cases, we aimed to determine the age of cancer diagnosis for dogs. Malignant tumors were diagnosed more often than benign neoplasms in older dogs. Intact females, large-sized, brachy-/dolichocephalic, and purebred dogs developed cancer at a younger age, but wide differences between breeds were noted. The earliest age at diagnosis was recorded for lymphomas and mast cell tumors. Due to the wide phenotypic and genetic variability of canines, breed-based screening schedules should be devised. Cancer is the most common cause of death in adult dogs. All dogs would benefit from early diagnosis, but there are no specific guidelines regarding the schedule of cancer screening in companion animals. The aim of this study was to retrospectively evaluate the age at diagnosis in Italian oncological canine patients. A total of 14,636 canine histologically confirmed neoplastic cases were coded according to the Vet-ICD-O-canine-1 and stratified by malignancy, sex, neutering status, breed, cephalic index, body size, and tumor type. Differences in age distribution were analyzed and the influence of these variables on the time of first malignancy diagnosis was assessed using an event history analysis model. The median age at diagnosis for benign and malignant tumors was 9 and 10 years, respectively. Intact and purebred dogs were diagnosed earlier, but the median age differed significantly by breed. The earliest age at diagnosis was recorded for lymphomas and mast cell tumors. The model showed an accelerating effect of large size, brachy- and dolichocephaly, and sexual integrity in female dogs on the time of malignancy diagnosis. Our results confirm that a "one-size-fits-all" approach to cancer screening is not accurate in dogs and provide relevant data that may lead to the establishment of breed-based screening schedules. [ABSTRACT FROM AUTHOR]

Simple Summary: This study focused on a 10-year-old dog presenting with weight loss, excessive drinking, and liver-related issues. The aim was to understand a rare type of lymphoma affecting the liver and spleen, known as hepatosplenic T-cell lymphoma. By examining tissue samples from the spleen, liver, and gallbladder, researchers identified abnormal cells indicating hepatosplenic T-cell lymphoma. Surgery and subsequent treatment with toceranib, a drug not commonly used for this lymphoma in dogs, led to a notable improvement in the dog's condition. This finding suggests toceranib could be an effective treatment option for hepatosplenic T-cell lymphoma in canines. The study's results highlight the potential of new treatments for rare diseases in pets, offering hope for improved care and outcomes in veterinary oncology. Toceranib phosphate (toceranib) is approved for canine mast cell tumor treatment. However, no long-term response to toceranib in canine HSTCL has been reported. Here, we describe a case of a 10-year-old castrated mixed-breed dog that presented with a 3-month history of weight loss, polydipsia, and polyuria. The clinicopathological and imaging abnormalities included icterus, biliary obstruction, and splenomegaly with multiple diffuse splenic hypoechoic nodules. On day 21, a cholecystectomy was performed to remove the obstruction, followed by a liver biopsy and splenectomy. Cytology of the spleen and liver showed many small lymphocytes with intracytoplasmic granules (sGLs). Splenic and hepatic infiltration of neoplastic CD3/granzyme B-positive small cells and lymphocytic cholecystitis with granzyme B-negative small cells were noted. T-cell receptor gene clonal rearrangements were observed in the liver tissues. The dog was diagnosed with a hepatosplenic T-cell lymphoma (HSTCL) of sGLs concurrent with lymphocytic cholecystitis. The icterus resolved after surgery, but there was progressive elevation of liver enzyme levels. Toceranib was administered from day 39, resulting in decreased liver enzyme levels, and the dog remained in good condition. The dog stayed in remission after toceranib administration and survived for 460 days. Toceranib should be considered an effective treatment option for canine HSTCL. [ABSTRACT FROM AUTHOR]

The "2024 ACVIM Forum Research Abstract Program" is a document that provides an index of research abstracts presented at the American College of Veterinary Internal Medicine (ACVIM) Forum. The abstracts cover a wide range of topics in veterinary medicine, including cardiology, equine health, gastroenterology, hematology, hepatology, immunology, infectious disease, nephrology/urology, neurology, kidney disease, feline chronic kidney disease, urinary tract health, and cancer treatment in dogs. It is important to note that the abstracts are not peer-reviewed and the opinions expressed in them are those of the authors and may not represent the views of the ACVIM. The document serves as a valuable resource for researchers and practitioners in the field, providing insights into ongoing research studies. However, further research is needed to confirm and expand upon the findings presented in these abstracts. [Extracted from the article]

Canine parvoviral enteritis remains one of the commonest causes of death in young dogs. This study aimed to determine serum total antioxidant capacity (TAC) and total oxidant status (TOS) levels in dogs with canine parvoviral enteritis (CPV) and reveal the risk factors of DIC formation. Thirty dogs were included in the study. The dogs were divided into two groups; the first group consisted of 20 dogs diagnosed with CPV (study group) and the other group consisted of 10 healthy dogs aged 0-12 months (control group). The mean TAC value was 0.354±0.018 mmol Trolox equiv./L in the control group and 0.295±0.007 mmol Trolox equiv./L in the study group. The mean TOS level was determined as 6.539±0.154 µmol H2O2/L in the control group and 7.934±0.364 µmol H2O2/L in the study group. The mean nitric oxide (NO) concentration was 18.613±0.856 µmol/L in the control group and 21.781±0.913 µmol/L in the study group. D-dimer levels were found to be 0.170±0.070 mg/dL in the control group and 2.585±0.584 mg/dL in the study group. As a result, it was demonstrated that it is essential to consider that oxidative stress increases and antioxidant capacity decreases in dogs with CPV and that disseminated intravascular coagulation (DIC) may develop in dogs with CPV. It is thought that considering oxidative stress and DIC during the treatment may contribute positively to prognosis and survival. [ABSTRACT FROM AUTHOR]

Introduction: Immunotherapy represents a promising breakthrough in cancer management and is being explored in canine melanomas. Dendritic cells (DCs) play a crucial role in priming T-cell-mediated immune reactions through the antigen-presenting function. Combining immunotherapy and radiation therapy may generate more substantial anti-cancer efficacy through immunomodulation. Objectives: Our research reported a preliminary result of the safety and outcome of a kind of immunotherapy, the allogeneic dendritic cell and autologous tumor cell fusion vaccine, alone or in combination with hypofractionated radiation therapy, in canine oral malignant melanoma. Methods: Two groups of dogs with histopathological diagnoses of oral malignant melanoma were recruited. In group 1 (DCRT), dogs received a combination of DC fusion vaccine and radiotherapy. In group 2 (DC), dogs received DC fusion vaccine alone. DC vaccination was given once every 2 weeks for four doses. Radiotherapy was performed weekly for five fractions. Dogs that received carboplatin were retrospectively collected as a control group (group 3). Results: Five dogs were included in group 1 (two stage II, three stage III), 11 in group 2 (three stage I/II, eight stage III/IV), and eight (two stage I/II, six stage III/IV) in the control group. Both DC and DCRT were well-tolerated, with only mild adverse events reported, including mucositis, gastrointestinal discomfort, and injection site reactions. The median progression-free intervals in groups 1, 2, and 3 were 214 (95% CI, NA, due to insufficient data), 100 (95% CI, 27– 237), and 42  days (95% CI, NA-170), respectively, which were not significantly different. The 1-year survival rates were 20, 54.5, and 12.5% in groups 1, 2, and 3. Dogs in the DCRT group exhibited significantly higher TGF-β signals than the DC group throughout the treatment course, indicating a possible higher degree of immunosuppression. Conclusion: The manuscript demonstrated the safety of dendritic cell/tumor cell fusion vaccine immunotherapy, alone or in combination with radiotherapy. The results support further expansion of this immunotherapy, modification of combination treatment and protocols, and investigation of combining DC vaccine with other treatment modalities. [ABSTRACT FROM AUTHOR]

Increased proliferation is a driver of tumorigenesis, and quantification of mitotic activity is a standard task for prognostication. This systematic review is an analysis of all available references on mitotic activity in feline tumors to provide an overview of the assessment methods and prognostic value. A systematic literature search in PubMed and Scopus and a nonsystematic search in Google Scholar were conducted. All articles on feline tumors that correlated mitotic activity with patient outcome were identified. Data analysis revealed that of the 42 eligible articles, mitotic count (MC, mitotic figures/tumor area) was evaluated in 39 studies, and mitotic index (MI, mitotic figures/tumor cells) in 3 studies. The risk of bias was considered high for most studies (26/42, 62%) based on small study populations, insufficient details of the MC/MI methods, and lack of statistical measures for diagnostic accuracy or effect on outcome. The MC/MI methods varied between studies. A significant association of MC with survival was determined in 20 of 28 (71%) studies (10 studies evaluated other outcome metrics or provided individual patient data), while 1 study found an inverse effect. Three tumor types had at least 4 studies, and a prognostic association with survival was found in 5 of 6 studies on mast cell tumors, 5 of 5 on mammary tumors, and 3 of 4 on soft-tissue sarcomas. MI was shown to correlate with survival for mammary tumors by 2 research groups; however, comparisons to MC were not conducted. Further studies with standardized mitotic activity methods and appropriate statistical analysis for discriminant ability of patient outcome are needed to infer the prognostic value of MC and MI. [ABSTRACT FROM AUTHOR]

One of the most relevant prognostic indices for tumors is cellular proliferation, which is most commonly measured by the mitotic activity in routine tumor sections. The goal of this systematic review was to analyze the methods and prognostic relevance of histologically measuring mitotic activity that have been reported for canine tumors in the literature. A total of 137 articles that correlated the mitotic activity in canine tumors with patient outcome were identified through a systematic (PubMed and Scopus) and nonsystematic (Google Scholar) literature search and eligibility screening process. Mitotic activity methods encompassed the mitotic count (MC, number of mitotic figures per tumor area) in 126 studies, presumably the MC (method not specified) in 6 studies, and the mitotic index (MI, number of mitotic figures per number of tumor cells) in 5 studies. A particularly high risk of bias was identified based on the available details of the MC methods and statistical analyses, which often did not quantify the prognostic discriminative ability of the MC and only reported P values. A significant association of the MC with survival was found in 72 of 109 (66%) studies. However, survival was evaluated by at least 3 studies in only 7 tumor types/groups, of which a prognostic relevance is apparent for mast cell tumors of the skin, cutaneous melanoma, and soft tissue tumor of the skin and subcutis. None of the studies using the MI found a prognostic relevance. This review highlights the need for more studies with standardized methods and appropriate analysis of the discriminative ability to prove the prognostic value of the MC and MI in various tumor types. Future studies are needed to evaluate the influence of the performance of individual pathologists on the appropriateness of prognostic thresholds and investigate methods to improve interobserver reproducibility. [ABSTRACT FROM AUTHOR]

Simple Summary: Canine cutaneous mast cell tumors have variable rates of recurrence and metastasis. We sought to evaluate how various prognostic factors affect survival, recurrence, and metastasis in a retrospective study of 90 dogs with cutaneous mast cell tumors treated with surgery and vinblastine chemotherapy. Factors evaluated included age, breed, grade, margins, local tumor control, mitotic count, lymph node metastasis, response to vinblastine chemotherapy in the gross disease setting, and timing of vinblastine in relation to surgery. Eighteen dogs received neoadjuvant vinblastine, and no dogs progressed locally before surgery. The use of neoadjuvant vinblastine was associated with a higher chance of local recurrence (p = 0.03) but not survival. Significantly shorter survival times were found for high-grade tumors (p < 0.001), grade 3 tumors (p < 0.001), and tumors with a mitotic count of >5 (p < 0.001). Dogs with grade 2/low grade cutaneous mast cell tumors lived longer than those with grade 2/high grade tumors (p < 0.001). Both grading systems and mitotic count were prognostic for survival in this population of dogs, supporting the need for standard reporting of histopathologic findings. Neoadjuvant chemotherapy can be effective in downsizing canine cutaneous mast cell tumors but does not influence survival. Objective: Canine cutaneous mast cell tumors (cMCTs) have variable rates of recurrence and metastasis. We evaluated how various prognostic factors affect survival, recurrence, and metastasis in dogs with cMCT who underwent surgery and vinblastine chemotherapy. Animals: 90 dogs with cMCT treated with surgery and vinblastine at a veterinary referral institution were included. Methods: Medical records were retrospectively reviewed. Prognostic factors were evaluated. Results: Most dogs (94%) had grade 2 or 3 cMCTs. Neoadjuvant vinblastine was used in 18 dogs, and none progressed locally before surgery. The use of neoadjuvant vinblastine was associated with a higher chance of local recurrence (p = 0.03) but not survival. Shorter survival times were found for tumors that were high-grade (p < 0.001), grade 3 (p < 0.001), or a MC of >5 (p < 0.001). Dogs with grade 2 tumors that were low-grade lived longer than those with high-grade tumors (p < 0.001). Histologic tumor-free margins and the ability to achieve local tumor control were not associated with outcome. Clinical Relevance: Both grading systems and MC were prognostic for survival in this population of dogs, supporting the need for the standard reporting of histopathologic findings. Neoadjuvant chemotherapy can be effective in downsizing cMCTs but does not influence survival. These findings are consistent with previous publications, showing the benefits of a more modern population of patients, surgical treatments, and histopathologic assessments. [ABSTRACT FROM AUTHOR]

Melanoma of the dog and cat poses a clinical challenge to veterinary practitioners across the globe. As knowledge evolves, so too do clinical practices. However, there remain uncertainties and controversies. There is value for the veterinary community at large in the generation of a contemporary wide-ranging guideline document. The aim of this project was therefore to assimilate the available published knowledge into a single accessible referenced resource and to provide expert clinical guidance to support professional colleagues as they navigate current melanoma challenges and controversies. Melanocytic tumors are common in dogs but rare in cats. The history and clinical signs relate to the anatomic site of the melanoma. Oral and subungual malignant melanomas are the most common malignant types in dogs. While many melanocytic tumors are heavily pigmented, making diagnosis relatively straightforward, melanin pigmentation is variable. A validated clinical stage scheme has been defined for canine oral melanoma. For all other locations and for feline melanoma, TNM-based staging applies. Certain histological characteristics have been shown to bear prognostic significance and can thus prove instructive in clinical decision making. Surgical resection using wide margins is currently the mainstay of therapy for the local control of melanomas, regardless of primary location. Radiotherapy forms an integral part of the management of canine oral melanomas, both as a primary and an adjuvant therapy. Adjuvant immunotherapy or chemotherapy is offered to patients at high risk of developing distant metastasis. Location is the major prognostic factor, although it is not completely predictive of local invasiveness and metastatic potential. There are no specific guidelines regarding referral considerations for dogs with melanoma, as this is likely based on a multitude of factors. The ultimate goal is to provide the best options for patients to extend quality of life and survival, either within the primary care or referral hospital setting. [ABSTRACT FROM AUTHOR]

Background: Acid suppressant drugs (ASDs) are commonly used to decrease gastric acid production, but some evidence exists that ASDs exert immunomodulatory effects. Such an effect has not been investigated in dogs for which ASDs are routinely prescribed. Hypothesis: Compared to naïve subjects, dogs treated with ASDs will exhibit differences in leukocyte ratios after treatment. Animals: Fifty‐one dogs with mast cell tumors (MCTs). Materials and Methods: Dogs with MCT that were either AS naïve or treated with ASDs (i.e., histamine‐2‐receptor antagonists [H2RA] or proton pump inhibitors [PPI]) were included in this retrospective study. Subjects were categorized into 3 treatment groups (AS naïve, H2RA treated, and PPI treated), and leukocyte ratios (neutrophil:eosinophil, lymphocyte:monocyte, and neutrophil:lymphocyte [NLR]) were calculated before and after treatment. A mixed effects analysis of variance on ranks was used to assess differences in ratios between treatments, between pre‐ and post‐treatment time points, and between pre‐ and post‐time points for each treatment. Concurrent administration of antihistamines, corticosteroids, and chemotherapeutic drugs was assessed as a confounding factor. Results: Famotidine (n = 14/14) and omeprazole (n = 12/12) were the only H2RA and PPI used, respectively. Dogs receiving famotidine had a significant increase in median NLR from pre‐ to post‐treatment (3.429; range, 1.417–15 to 5.631; range, 2.654–92; P < 0.01) compared to PPI treated or AS naïve dogs. No differences existed in chemotherapeutic drug or corticosteroid use between groups. Conclusions: A significant difference in NLR was identified in famotidine treated dogs compared with omeprazole treated or AS naïve dogs. [ABSTRACT FROM AUTHOR]

Background: Dogs with retroperitoneal hemangiosarcoma (HSA) exhibit variable postoperative median survival times (MST). Objective: To retrospectively evaluate the prognostic value of selected tumour‐related factors, such as tumour size, rupture, invasion into adjacent tissue, involvement of lymph node and distant metastasis, they were analysed in dogs with retroperitoneal HSA. Methods: Ten dogs with retroperitoneal HSA managed solely with surgical excision were reviewed and compared with spleen (71) and liver (9) HSA. The Kaplan–Meier method and log‐rank analysis were used compare MSTs between factors. Multivariable Cox proportional‐hazard analysis was used to compare differences between arising sites. Results: Retroperitoneal HSA showed comparatively longer postoperative MST compared with that of spleen and liver HSA and demonstrated significantly longer MST (p = 0.003) for tumours ≥5 cm (195 days) than <5 cm (70 days). Spleen HSA revealed significantly shorter MSTs in involvement of distant lymph nodes (23 days) and distant metastasis (39 days) than those in negative (83 days, p = 0.002 and 110 days, p < 0.001, respectively). Liver HSA also revealed significantly shorter MST (16.5 days compared with 98 days, p = 0.003) for distant metastasis. Additionally, hazard ratios (HRs) and their forest plot for overall HSA revealed as poor prognostic factors, arising sites (spleen; HR 2.78, p = 0.016 and liver; HR 3.62, p = 0.019), involvement of distant lymph nodes (HR 2.43, p = 0.014), and distant metastasis (HR 2.86, p < 0.001), and as better prognostic factor of tumour size ≥5 cm (HR 0.53, p = 0.037). Conclusion: In combination with overall HSA, retroperitoneal HSA shows comparatively longer postoperative MST compared to spleen and liver HSA, associated with tumour size ≥5 cm suggesting better prognostic factor. [ABSTRACT FROM AUTHOR]

Background: Mammary adenocarcinomas are one of the most common tumour diseases in bitches. The relationship between oxidative stress and the degree of malignancy of the tumour has not been sufficiently researched in veterinary medicine. Objectives: The main objective was to investigate the potential role of MDA as a practice‐relevant biomarker for the assessment of systemic oxidative stress and to determine whether this parameter can indicate the malignancy grade of a mammary adenocarcinoma. Methods: In the present pilot study, MDA plasma concentrations were analysed in 55 bitches with (n = 28) and without (n027) malignant adenocarcinomas of the mammary gland using two different measurement methods and the relationship to tumour size was investigated. Results: The mean MDA concentration measured by enzyme‐linked immunosorbent assay (ELISA) was 289 ng/mL (range 365–634 ng/mL) in dogs with grade 1 adenocarcinoma (n = 13), 288.5 ng/mL (range 85–752 ng/mL) in dogs with grade 2 adenocarcinoma (n = 10), 332 ng/mL (range 239–947 ng/mL) in dogs with grade 3 (n = 5) adenocarcinoma and 293 ng/mL (range 175–549 ng/mL) in dogs without a mammary tumour (n = 27). When MDA was measured by HPLC, the average MDA concentration in the study group (n = 11) was 0.24 µmol/L (range 0.16–0.37) and that of the control group (n = 15) was 0.27 µmol/L (range 0.16–1.62). Thus, there were no significant differences between the study group with malignant adenocarcinomas and the control group in both examination methods (p > 0.05). Furthermore, there was no correlation between the MDA concentrations and the approximate volume of the mammary tumour. Conclusion: The results highlight the challenges of providing a prognosis for the malignancy of a mammary adenocarcinoma based on MDA concentrations in plasma using ELISA or HPLC. As a result, histopathological examination remains the gold standard for diagnosing and differentiating adenocarcinomas of the mammary gland. [ABSTRACT FROM AUTHOR]

Introduction: Canine cutaneous histiocytoma (CCH) is a benign tumor frequently occurring in young dogs which is derived from Langerhans cells (LC). Distinguishing features of this tumor are its spontaneous regression following a rapid tumor growth. Impaired control of immune checkpoints during tumor development and progression is a widespread phenomenon which may result in an absent or ineffective immune response. The interaction between the inflammatory response and the expression of immune checkpoint molecules is only partially described in this tumor type. The aim of this study was to identify immune checkpoint molecules and molecules from the interferon-mediated immune response that are involved in the regression of CCH. Methods: Forty-eight CCH derived from dogs = 4 years of age were assigned to one of four groups according to the severity and distribution of lymphocyte infiltration. Using immunohistochemistry and whole-slide image scans of consecutive sections the expression of programmed death protein ligand 1 (PDL1), CD80, CD86, Survivin, forkhead box protein 3, Ki-67, cleaved caspase-3, CD3, and mx1 were investigated. RNA in-situ hybridization was performed for transcripts of mx1 and interferon-γ. Results: Neoplastic cells showed an expression of PD-L1, CD80, CD86, and Survivin. The density of CD80 expressing cells was negatively correlated with regression while the density of cleaved caspase-3 positive cells increased with regression. Mx1 transcripts and protein were predominantly localized in neoplastic cells while interferon-γ transcripts were most frequently detected in T-cells. Conclusion: The expression of the immune checkpoint molecules CD86 and PD-L1 and particularly the reduced expression of CD80 in groups 3 and 4 indicate an influence of the investigated immune checkpoints on tumor regression. In parallel an activation of the apoptotic cascade during regression is suggested. Finally, the detection of mx1 within the neoplasm pinpoints to a yet undisclosed role of anti-cellular signaling in tumor immunity. [ABSTRACT FROM AUTHOR]

This article provides information on the radiographic imaging of thoracic lymph nodes in dogs. It highlights the importance of understanding the locations and drainage patterns of these lymph nodes for accurate interpretation of thoracic radiographs and differential diagnoses. The article specifically focuses on the sternal, mediastinal, and tracheobronchial lymph nodes, discussing their normal appearance, potential causes of enlargement, and diagnostic considerations. It also mentions that lymphadenomegaly in adult dogs is often associated with neoplastic or inflammatory conditions, while antigenic stimulation and immune system development are additional considerations for young animals. The text emphasizes the significance of understanding the lymphatic system in dogs and specifically focuses on the tracheobronchial lymph nodes, which are commonly affected by neoplasia and infections. This knowledge can assist veterinarians in diagnosing and selecting appropriate testing for dogs with thoracic lymphadenomegaly. [Extracted from the article]

This article provides an overview of recent advancements in veterinary cancer immunology, focusing on how the immune system interacts with animal cancer cells. It discusses novel immunotherapeutic approaches, such as cancer vaccines and monoclonal antibodies, that have shown promise in treating canine cancers. Comparative oncology, which examines cancer across different species, is highlighted as a valuable approach for identifying common mechanisms and potential treatments. The article also mentions the potential of chimeric antigen receptors (CARs) in veterinary immuno-oncology, although their use in veterinary medicine is still under development. The document is a collection of research articles covering various topics related to cancer treatment in animals, providing new insights and potential therapeutic strategies for veterinary oncology. Ongoing research in this field is crucial for improving cancer management and treatment options for dogs. [Extracted from the article]

Canine gastrointestinal (GI) and hepatosplenic (HS) high-grade (large cell) lymphomas are uncommon forms of canine lymphomas, with a very poor response to chemotherapy and a very poor prognosis. Currently, there are no established effective chemotherapy protocols for canine GI/HS lymphomas. This case series aimed to retrospectively evaluate the efficacy of lomustine-based protocols L-LOP (L-asparaginase, lomustine, vincristine, and prednisolone) and L-LOPP (with the addition of procarbazine) for treatment of canine GI/ HS lymphomas. Medical records of dogs with cytologically or histologically diagnosed lymphoma at CityU Veterinary Medical Centre from 2019 to 2022 were retrospectively reviewed. The L-LOP/LOPP treatment protocol was well tolerated with rare severe adverse events. Median progression-free survival for GI and HS lymphoma was 56 days (range, 10-274 days) and 57 days (range 8-135 days) respectively; while median survival time for GI and HS lymphoma was 93 days (range 10-325 days) and 210 days (range 8-240 days) respectively. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is the most common malignant liver tumor in dogs. Although surgical resection is a major treatment option for canine HCC, there are no distinct strategies for unresectable tumor subtypes or adjuvant chemotherapy for tumors with positive margins. We aimed to establish and characterize novel HCC cell lines from canine patients. Methods: The cellular morphology, general growth features and tumorigenicity of the established cell lines were evaluated. We also examined the sensitivity of the cell lines to multi-target tyrosine kinase inhibitors (TKIs). Results: We established novel canine HCC cell lines from hepatic tumors and an additional kidney tumor of six canine patients. All cell lines showed colony forming and migratory ability. KU-cHCC-001 and KU-cHCC-001-Kidney, two cell lines exhibiting high epithelial-mesenchymal transition characteristics, showed tumorigenicity in xenografted mice. Toceranib, a veterinary TKI that targets vascular endothelial growth factor (VEGFR)/platelet-derived growth factor receptor (PDGFR)/c-kit, effectively inhibited the mitogen-activated protein kinase pathway and induced apoptosis. The established canine HCC cell lines showed greater sensitivity to toceranib than to sorafenib, a first-line treatment for human HCC targeting RAF/VEGFR/PDGFR. Sorafenib showed improved anti-tumor effects when co-treated with SCH772984, an extracellular signal-regulated kinase inhibitor. Conclusion: Our study suggests new therapeutic strategies for canine HCC, and these cell lines are valuable research materials for understanding HCC tumor biology in both humans and dogs. [ABSTRACT FROM AUTHOR]

This article discusses a study that examines the role of interleukin 31 (IL-31) in the development of atopic dermatitis (AD) in dogs. The researchers used a naturally occurring canine model of AD to investigate IL-31 transcription in the skin during acute and chronic inflammation. They found that IL-31 transcription was low or undetectable during acute inflammation and increased during chronic inflammation. The study suggests that IL-31 transcription in atopic skin may be attributable to infiltrating cells, such as eosinophils and macrophages, rather than CD3+ T cells. Further research is needed to identify the specific cells involved in IL-31 signaling in atopic skin. [Extracted from the article]

The aim of this study is to investigate the correlation between the incidence of spontaneous tumours of various origins and the localisation in dogs with sex, breed, and age factors. A total of 360 tumours with various localisation were studied pathomorphologically. Histopathologic data sets from 360 dog tissue samples were processed and statistically examined. A chi-square test of independence was conducted to examine the relationships among the various levels of the specified variables. Logistic regression models were employed for dichotomous outcomes to ascertain the influence of certain explanatory variables on the tumour types. Characteristic pathomorphological changes observed during examination of dogs with oncologic diseases were determined. The most common neoplasms were mammary tumours, accounting for 43% of the cases. The mammary gland tumours were most common in mongrel dogs (25%), with German Shepherds (17.3%), Poodles, Dachshunds, Central Asian Shepherds (6.7% each), and Rottweilers (5.7%) following. The highest frequency of these tumours appeared at 8 years of age, predominantly originating from the ductal epithelium, which represented 46.4% of all the malignant cases. [ABSTRACT FROM AUTHOR]

We report on a case of a two-year-old male dog, breed chow-chow, who suffered from urethral fistula as a result of ureterolithiasis. The urethral defect was identified intraoperatively with methylene blue. An autologous regenerative approach was combined with surgical closure of the defect, due to the well-known healing issues of the urethral wall in such conditions. A part of abdominal fat tissue was dissected to produce microfragmented adipose tissue containing mesenchymal stem cells, which was combined with platelet-rich plasma. The final product was applied in the area around the urethral defect closure. One month after the procedure, healing was confirmed with positivecontrast cystography. This therapeutic approach yielded success, and the follow-up period of one year was uneventful. The observed positive outcome of this approach in the canine model may be considered as a starting point for investigating the translational potential of the treatment in human medicine. [ABSTRACT FROM AUTHOR]

We describe here a case of canine mammary benign mixed tumor with sebaceous metaplasia in the right fifth mammary gland of an eight-year-old, intact female Poodle dog. Grossly, the mass was firm with off-white, poorly lobulated cut surfaces. Histologically, the luminal epithelial cells and myoepithelial cells proliferated with cartilage formation and focal squamous metaplasia. Moreover, a large number of nests of various sizes, which were filled with foamy cells in the center and associated with basaloid reserve-like cells in the periphery, showed sebaceous gland-like structures. Immunohistochemically, myoepithelial cells and reserve-like cells in the metaplastic sebaceous gland-like structures were CK14, α-smooth muscle actin (α-SMA) and p63 positive, suggesting a possibility that these two components may have a common cell of origin. [ABSTRACT FROM AUTHOR]

Objectives: To report the histopathological diagnosis of both anal sacs in dogs undergoing bilateral anal sacculectomy for the treatment of unilateral apocrine gland anal sac adenocarcinoma and to compare the surgical complication rate associated with this procedure in this population with previously published literature. Materials and Methods: Records were retrospectively reviewed for dogs that underwent bilateral anal sacculectomy for the treatment of apparently unilateral apocrine gland anal sac adenocarcinoma, at a single institute between 2019 and 2023. Clinical staging, surgical treatment, histological findings, intra‐ and postoperative complications were evaluated. Results: Thirty‐five dogs were included. Only five of 35 (14%) dogs were found to have histologically normal contralateral anal sacs. Non‐neoplastic anal sac disease was found in 23 of 35 (66%) dogs and bilateral apocrine gland anal sac adenocarcinoma was seen in seven of 35 (20%) dogs. None of the dogs diagnosed with bilateral neoplasia had evidence of bilateral neoplasia before surgery despite a thorough work‐up. Complications attributable to the primary tumour removal were seen in 9% of dogs intraoperatively and 14% of dogs postoperatively, commonly tumour capsule disruption and surgical site infection, respectively. Clinical Significance: Bilateral anal sac disease was diagnosed histologically in the majority of presumed normal anal sacs, with 20% of cases being found to have bilateral apocrine gland anal sac adenocarcinoma. The surgical complication rates of this cohort were comparable to those reported for unilateral anal sacculectomy alone. These findings promote and encourage the use of bilateral anal sacculectomy in cases of suspected unilateral anal sac neoplasia. [ABSTRACT FROM AUTHOR]

Background: Intervertebral disk (IVD) degeneration affects both humans and canines and is a major cause of low back pain (LBP). Mast cell (MC) and macrophage (MØ) infiltration has been identified in the pathogenesis of IVD degeneration (IVDD) in the human and rodent model but remains understudied in the canine. MC degranulation in the IVD leads to a pro‐inflammatory cascade and activates protease activated receptor 2 (PAR2) on IVD cells. The objectives of the present study are to: (1) highlight the pathophysiological changes observed in the degenerate canine IVD, (2) further characterize the inflammatory effect of MCs co‐cultured with canine nucleus pulposus (NP) cells, (3) evaluate the effect of construct stiffness on NP and MCs, and (4) identify potential therapeutics to mitigate pathologic changes in the IVD microenvironment. Methods: Canine IVD tissue was isolated from healthy autopsy research dogs (beagle) and pet dogs undergoing laminectomy for IVD herniation. Morphology, protein content, and inflammatory markers were assessed. NP cells isolated from healthy autopsy (Mongrel hounds) tissue were co‐cultured with canine MCs within agarose constructs and treated with cromolyn sodium (CS) and PAR2 antagonist (PAR2A). Gene expression, sulfated glycosaminoglycan content, and stiffness of constructs were assessed. Results: CD 31+ blood vessels, mast cell tryptase, and macrophage CD 163+ were increased in the degenerate surgical canine tissue compared to healthy autopsy. Pro‐inflammatory genes were upregulated when canine NP cells were co‐cultured with MCs and the stiffer microenvironment enhanced these effects. Treatment with CS and PAR2 inhibitors mediated key pro‐inflammatory markers in canine NP cells. Conclusion: There is increased MC, MØs, and vascular ingrowth in the degenerate canine IVD tissue, similar to observations in the clinical population with IVDD and LBP. MCs co‐cultured with canine NP cells drive inflammation, and CS and PAR2A are potential therapeutics that may mitigate the pathophysiology of IVDD in vitro. [ABSTRACT FROM AUTHOR]

Background: Intervertebral disc degeneration is frequent in dogs and can be associated with symptoms and functional impairments. The degree of disc degeneration can be assessed on T2‐weighted MRI scans using the Pfirrmann classification scheme, which was developed for the human spine. However, it could also be used to quantify the effectiveness of disc regeneration therapies. We developed and tested a deep learning tool able to automatically score the degree of disc degeneration in dog spines, starting from an existing model designed to process images of human patients. Methods: MRI midsagittal scans of 5991 lumbar discs of dog patients were collected and manually evaluated with the Pfirrmann scheme and a modified scheme with transitional grades. A deep learning model was trained to classify the disc images based on the two schemes and tested by comparing its performance with the model processing human images. Results: The determination of the Pfirrmann grade showed sensitivities higher than 83% for all degeneration grades, except for grade 5, which is rare in dog spines, and high specificities. In comparison, the correspondent human model had slightly higher sensitivities, on average 90% versus 85% for the canine model. The modified scheme with the fractional grades did not show significant advantages with respect to the original Pfirrmann grades. Conclusions: The novel tool was able to accurately and reliably score the severity of disc degeneration in dogs, although with a performance inferior than that of the human model. The tool has potential in the clinical management of disc degeneration in canine patients as well as in longitudinal studies evaluating regenerative therapies in dogs used as animal models of human disorders. [ABSTRACT FROM AUTHOR]

Lymphoma is one of the most frequent hematopoietic tumors in dogs and shares similar features with human counterparts. MicroRNAs (miRNA, small noncoding RNAs) are pivotal in gene regulation fine tuning and cancer hallmarks are influenced by their aberrant expression. Consequently, miRNA biomarkers may assist predicting therapeutic response and clinical outcome by providing less-invasive novel diagnostics tools. The aim of this study was to detect dysregulated miRNAs in lymphomatous lymph node tissues in comparison to lymph node material or PBMCs from healthy control dogs. Potential significant differences in miRNA expression profiles between four lymphoma entities were evaluated. A customized PCR array was utilized to profile 89 canine target miRNAs. Quantification was performed using qPCR, relative expression was determined by the delta-delta Ct method, and p-values were calculated with student's t-test. In the 14 diffuse large B-cell lymphoma (DLBCL) patients, 28 and 24 different miRNAs were significantly dysregulated compared to lymph node material or PBMCs. Sixteen miRNAs occurred in both control groups, with 12 miRNAs being down- and four miRNAs being upregulated. The six peripheral T-cell lymphoma (PTCL) samples showed 24 and 25 dysregulated miRNAs when compared to the healthy controls. A combined analysis of DLBCL and PTCL samples revealed seven shared and 19 differently expressed miRNAs. Potential biomarkers in T- and B-cell lymphoma could be the miRNA-17/92 cluster and miRNA-181-family together with miRNA-34a and miRNA-150. Diagnostic utility of potential biomarkers must be validated in larger, prospective cohorts of canine lymphoma cases and in higher numbers of physiological patient material. [ABSTRACT FROM AUTHOR]

Simple Summary: Rodents have become increasingly popular as household pets, but few studies have focused on tumors in pet rodents. Pet rodents differ from their laboratory counterparts in many aspects such as geographical preference of pet species or breeds, household raising conditions, population density, and life expectancy. Therefore, it is worth conducting this pathological study of 77 spontaneous tumors from 70 pet rodents. Overall, mammary gland tumors were common. In the meantime, mouse mammary tumor virus (MMTV)-like sequences were found in the tissues of dogs, cats, and humans, raising the concern of whether these pets may incidentally serve as a vehicle for the cross-species transmission of MMTV to household personnel. For that purpose, nuclei acid extracted from the formalin-fixed paraffine-embedded tissues of 20 rodent mammary gland tumors was detected for MMTV env gene sequences. All tumors revealed negative results of MMTV detection. Compared to the number of studies on the neoplasms of laboratory rodents, fewer studies have focused on spontaneous neoplasms in pet rodents. Notably, the mouse mammary tumor virus (MMTV) is associated with mammary tumors in rodents. In this study, 77 tumors and tumor-like lesions of biopsy samples were collected from 70 pet rodents, including hamsters (n = 47), guinea pigs (n = 16), unknown species (n = 4), rats (n = 2), and a gerbil. Fifty tumors were collected from 47 hamsters, in which the most common tumors were mammary tumors (13/50), followed by fibrosarcoma (9/50), mast cell tumors (4/50), and squamous cell carcinoma (4/50). The collected subtypes of mammary tumors in hamsters included tubular carcinoma (n = 5), tubular adenoma (n = 4), carcinoma and malignant myoepithelioma (n = 1), simple tubular carcinoma (n = 1), adenosquamous carcinoma (n = 1), and tubulopapillary adenoma (n = 1). In addition, twenty tumors were collected from guinea pigs, in which the most common tumor was lipoma (6/20), followed by adenocarcinoma of the mammary gland (4/20), trichofolliculoma (2/20), and collagenous hamartomas (2/20). In guinea pigs, the subtypes of mammary gland tumors were tubular carcinoma (n = 2), tubular and solid carcinoma (n = 1), and tubulopapillary carcinoma (n = 1). In 20 cases of mammary tumors, MMTV was not detected, implicating no evidence of MMTV infection in mammary oncogenesis in pet rodents in Taiwan. [ABSTRACT FROM AUTHOR]

Introduction: In veterinary medicine, cancer is the leading cause of death in companion animals, and mammary gland tumors represent the most common neoplasm in female dogs. Several epidemiological risk factors, such as age, breed, hormones, diet, and obesity have been reported to be relevant for canine mammary tumors. Nowadays, the gold standard for diagnosis of caninemammary tumors is the pathological examination of the suspected tissue. However, tumor grade can only be assessed after surgical removal or biopsy of the altered tissue. Therefore, in cases of tumors that could be surgically removed, it would be very helpful to be able to predict the biological behavior of the tumor, before performing any surgery. Since, inflammation constitutes part of the tumor microenvironment and it influences each step of tumorigenesis, cellular and biochemical blood markers of systemic inflammation, such as the neutrophil to lymphocyte ratio (NLR) and the albumin to globulin ratio (AGR) have been proposed as prognostic factors for human cancer development. The NLR and the AGR have not been explored enough as prognostic factors for cancer development in veterinary medicine. Methods: To determine the prognostic value of NLR in canine mammary tumors, clinical records including biochemistry and hematological studies of female dogs with mammary tumors and of control healthy dogs, were used to determine the pre-treatment NLR and AGR. Other clinical data included age, breed, tumor size, histological tumor grade, and survival time after surgery. Results and discussion: It was found that a higher pre-treatment NLR value (NLR > 5) associates with less survival rate. In contrast, the AGR did not show any predictive value on the malignancy of the tumor. However, by combining the NLR with AGR, age of the dog, and tumor size in a principal component analysis (PCA), the grade of the tumor and survival after surgery could be appropriately predicted. These data strongly suggest that pre-treatmentNLR values have a prognostic value for the survival rate after surgery of dogs with mammary tumors. [ABSTRACT FROM AUTHOR]

Introduction: Canine bacterial keratitis is a corneal infection that causes various symptoms, including visual impairment, and necessitates eye removal in severe cases. Staphylococcus pseudintermedius is a pathogen that causes significant bacterial keratitis in canine patients. Moreover, multi-drug resistant Staphylococcus pseudintermedius (MDRSP) has been reported in both humans and animals. Regarding treatment failure against multi-drug resistant (MDR) pathogens with classic antibiotics, antimicrobial compounds derived from probiotics have been suggested as an alternative approach. Methods: Ligilactobacillus animalis SWLA-1 strain and its cell-free supernatant (CFS) have previously demonstrated potent antimicrobial activity against various MDR pathogenic bacteria. Based on this finding, we evaluated the antistaphylococcal activity of CFS derived from Ligilactobacillus animalis SWLA-1 against MDRSP in a newly established ex vivo canine corneal infection model using fresh canine corneoscleral rims. Additionally, an in vitro cytotoxicity test using human keratocytes was performed. Results and Discussion: CFS significantly inhibited the growth of MDRSP in the novel ex vivo model and did not exhibit any significant toxicity against keratocytes in vitro. Based on these results, the antimicrobial compounds in CFS show potential as a novel approach for MDR staphylococcal keratitis treatment. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to describe clinical and histologic characteristics of eyelid (LMCT) and conjunctival (CMCT) mast cell tumors in dogs and cats presented to a referral clinic in Germany. Animal Studied: Medical records were reviewed to identify dogs and cats diagnosed with LMCTs or CMCTs between 2006 and 2020. Results: LMCT were diagnosed in 31 patients and were cutaneous (n = 28; 20 dogs and 8 cats) or subcutaneous (three dogs). Five cases involved the mucocutaneous junction (four dogs, one cat). CMCTs occurred only in dogs (n = 3). At the time of presentation two of the four canine LMCT cases involving the mucocutaneous junction had metastasized to a mandibular lymph node. When applying the Kiupel system, both these cases were categorized as high grade. 85.7% (18/21) of the canine (19 cutaneous and 2 subcutaneous) LMCT and all CMCT cases were categorized as Kiupel low grade. No local recurrences occurred in all LMCT cases in which clean surgical margins were obtained (n = 18, mean surgical margin width: dogs 9.4 mm, cats 3.8 mm). Two cats (2/4) and four dogs (4/7) with questionable or incomplete surgical margins experienced local recurrences (mean time to recurrence of 180 and 637 days in dogs and cats, respectively). Conclusion: Recurrence of low‐grade LMCTs and CMCTs following excision with clean margins is rare. Tumors involving the mucocutaneous junction may be of higher grade and prone to lymphatic metastasis. [ABSTRACT FROM AUTHOR]

Background: The therapeutic role and prognostic relevance of lymphadenectomy in mast cell tumor (MCT) has historically been evaluated on regional rather than sentinel lymph nodes. Hypothesis/Objectives: To update information about the association of histological nodal (HN) classes with clinical outcome in dogs with MCT after tumor excision and extirpation of normal‐sized sentinel nodes (SLN) guided by radiopharmaceutical. Animals: Ninety‐four dogs with histologically‐confirmed treatment‐naïve MCT (71 cutaneous, 22 subcutaneous and 1 conjunctival MCT) were included if without: distant metastases, lymphadenomegaly, concurrent mixed cutaneous, and subcutaneous MCT. Methods: This was a monoistitutional cohort study. Tumors characteristics were retrieved and SLNs were classified according to Weishaar's system. Incidence of MCT‐related events (local, nodal, distant relapse), de novo MCT or other tumors and death (MCT‐related and non‐MCT‐related), were recorded. Incidence curves were compared among the HN classes. Results: Twenty‐seven dogs had HN0, 19 HN1, 37 HN2, and 11 HN3 SLN. Thirteen (2 HN0, 4 HN2, and 7 HN3) received adjuvant chemotherapies. Kiupel high grade, increasing number of SLN and lymphocentrums were associated with higher HN classes. Five dogs died for MCT‐related causes: 1 low‐grade (HN0) and 1 subcutaneous (HN3) had a local relapse, 2 high‐grade had distant relapse (HN3‐HN0) and 1 dog developed disease progression from a de novo subcutaneous MCT. No nodal relapse was registered. Fourteen dogs developed de novo MCTs. Conclusion/Discussion: Low grade/low‐risk MCT with nonpalpable and normal sized SLN have a favorable outcome independently from the HN. Result should be considered strictly related to the successful SLN detection guided pre‐ and intraoperative by radiopharmaceutical markers. [ABSTRACT FROM AUTHOR]

Five types of round cell tumors found in dogs are mast cell tumors (MCT), lymphoma, plasma cell tumors, histiocytoma, and transmissible venereal tumors (TVT). This study focuses on the occurrence and cytopathology of these tumors in dogs of Meerut, Uttar Pradesh (India), spanning the period from 2018 to 2022. A total of 147 samples were gathered from different sites of dogs, notably 95 samples from vaginal specimens, 24 from nodular skin swellings, 7 samples from penile growths, 5 from lymph nodes, and 16 were from various skin lesions. The analysis of these samples revealed 4 cases of lymphoma, 3 cases of MCT, and 28 cases of TVT. In lymphoma, one case was identified as cutaneous lymphoma, while three cases were associated with lymph nodes. Cutaneous lymphoma exhibited numerous small and medium-sized lymphocytes. Lymph node samples exhibited a substantial presence of large-sized and medium-sized lymphocytes. TVT emerged as the most prevalent round cell tumor, observed in both genital and extragenital forms. Extragenital TVT predominantly affected the skin. In mast cell tumors, cells demonstrated round characteristics, with a notable granules in the cytoplasm and infiltration of eosinophils. Minimal anisocytosis and anisokaryosis, coupled with a high nuclear-to-cytoplasmic ratio, were evident in these tumors. [ABSTRACT FROM AUTHOR]

Background: The increasing interest in platelet‐based therapies has underwritten the development of novel veterinary regenerative treatments. The haemoderivative platelet‐rich fibrin (PRF) comprises abundant concentrations of platelets and leucocytes, above the physiologic baseline, which are considered essential elements for wound regeneration, stimulating local angiogenesis, cellular migration, proliferation and differentiation, considered essential for skin repair. Objectives: This study aimed to describe the treatment of eight dogs with naturally occurring cutaneous wounds, where autologous PRF therapy was applied, using a protocol developed by our group. Methods: Eight dogs, aged between 7‐month and 9‐year old, from different breeds and sexes, were enrolled in this study. Four of these wounds were clinically infected. In three cases, two PRF treatments were performed during the first week of treatment, followed by single weekly treatments from the second week onwards, until exophytic granulation tissues were present. In each case, the treatment was finalized only when complete wound closure was achieved. Wounds did not receive topical antiseptics, antibiotics or topical drugs to promote wound healing during the treatment. Results: PRF‐grafting treatments were well tolerated in all treated wounds, inducing significant granulation tissue formation. PRF clots acted as a natural tissue filler, promoting epithelization and wound closure, without the requirement of topical antimicrobial/antiseptics application, or additional surgical debridement. Evident skin contraction was recorded in larger injuries and all the treatments resulted in vestigial aesthetic scars where hair growth was also observed. Conclusions: PRF‐therapy obtained promising results, as an alternative wound treatment, revealing a biological regenerative action, prompting the natural skin healing process. [ABSTRACT FROM AUTHOR]

Disease monitoring of amphibian assurance populations is an important buffer against ongoing global extinctions. This study documents a high incidence of neoplasia in a zoo-managed assurance population of Puerto Rican crested toads (Peltophryne lemur ; PRCTs). Over 5 years, neoplasia was diagnosed in 17/49 (35%) submitted adult PRCTs and was the cause of death or euthanasia in 13/17 (72%). Most toads were male (16/17; 94%) and 6 to 11-years-old (average 8.1 years). Notably, seven toads (41%) had multiple neoplasms. Of the 29 neoplasms identified, 17 (59%) were cutaneous or subcutaneous. The most common neoplasms included mast cell tumors (MCTs; 8/29; 28%), histiocytic sarcomas (6/29; 21%), lymphoma/leukemia (4/29; 14%), and squamous cell carcinomas (3/29; 10%). Distant metastases were documented in 6/8 (75%) toads with MCTs. Causes for neoplasia in this population were not determined though may include genetic or environmental factors. Continued investigations of managed endangered amphibians will help elucidate mechanisms of carcinogenesis. [ABSTRACT FROM AUTHOR]

A 7-year-old Lhasa Apso presented with a history of left thoracic limb lameness and neck pain. Magnetic resonance imaging revealed a well-defined, extradural lesion that was hyperintense on T1-weighted (T1W) images and isointense on T2-weighted (T2W) images and T2* images located at the left lamina of the C4 vertebra. Computed tomography showed an isoattenuating and contrastenhancing mass centered on the left C4 vertebral lamina with associated osteolysis. The mass was surgically debulked, and histopathology revealed a malignant melanocytic tumour. The patient recovered completely and received radiotherapy and three doses of the melanoma vaccine as adjunctive treatment. Eighteen months following treatment, the patient presented with neck pain again, but further investigations were declined at this stage, and the patient was euthanised. To the author's knowledge, this is the first case report describing the imaging characteristics of a cervical extradural melanocytic tumour in a dog. This case illustrates the MRI and CT imaging features and treatment of a canine melanocytic tumour of the cervical vertebrae. [ABSTRACT FROM AUTHOR]

Canine circovirus (CanineCV) is a contagious virus that causes severe gastroenteritis, diarrhea, respiratory disease, and vasculitis, often resulting in fatality among infected dogs. In this study, a recombinant Capsid protein (rCap) of CanineCV was expressed in the Escherichia coli (E. coli) Rosetta (DE3) pLysS host cell, followed by affinity purification, and then analyzed by SDSPAGE, revealing a molecular weight of approximately 31 kDa. The antigenicity of the CanineCV rCap protein was confirmed through recognition by a rabbit anti-CanineCV rCap protein polyclonal antibody (PoAb). Additionally, the reactivity and specificity of this PoAb were assessed using indirect enzymelinked immunosorbent assay (ELISA) and Western blot analysis before applying in an immunohistochemistry (IHC), namely, immunoperoxidase detection. The immunoperoxidase assay using rabbit anti-CanineCV rCap protein PoAb demonstrated that the CanineCV Cap protein was predominantly located in immune cells, especially lymphocytes and macrophages, within the spleen, lung, tracheobronchial lymph nodes, small intestine, and kidney. Similarly, the Cap protein was also found in pneumocytes in the lung and renal tubular epithelial cells in the kidney. These findings reflected the biological activity and cell tropism of the virus. Therefore, the recombinant Cap protein and its PoAb could be used for the development of a valuable diagnostic tool for CanineCV detection. [ABSTRACT FROM AUTHOR]

Monitoring neoplasms in standardized registries facilitates epidemiologic studies of risk factors for tumor development and predisposition. In an observational study, we determined incidence rates (IR) and malignant tumor incidence rate ratios (IRR) by age, sex, and breed in Swiss dogs using demographic data from the official Swiss dog registration database Amicus. The dataset analyzed included 54'986 tumors diagnosed by histology and cytology in four Swiss veterinary pathology laboratories between 2008 and 2020. Diagnoses were coded according to the Vet-ICD-O-canine-1 system. Most tumors occurred in the skin (n = 19'045; 34.64%), soft tissues (n = 11'092; 20.17%), and mammary glands (n = 7'974; 14.50%). The IRs for all and for malignant tumors were 775/100'000 dog-years at risk (95%CI 764–777) and 338/100'000 dog-years at risk (95%CI 333–342), respectively. Females (850; 95%CI 834–853) had a higher overall tumor IR than males (679; 95%CI 666–684). The highest tumor IR was found at 11 years of age (1'857; 95%CI 1'780–1'867). Potential novel breed-specific predispositions were uncovered, with high IRs for several benign and malignant tumors in Polski Owczarek Nizinnys (overall IR: 3'303; 95%CI 2'502–3'864) and high IRs for malignant tumors in Russian Black Terriers (melanomas: 345; 95%CI 138–708), Field Spaniels (adenocarcinomas: 376; CI95% 138–817), Dogo Argentinos (mast cell tumors: 844; CI95% 591–1'169), King Charles Spaniels and Manchester Terriers (lymphomas: 319; CI95% 137–627 and 302; CI95% 98–704, respectively), Landseers (osteosarcomas: 74; CI95% 15–216), Bouvier des Flandres (hemangiosarcomas: 127; CI95% 26–371), and Bearded Collies and Cane Corso Italianos (gliomas: 91; CI95% 45–162 and 34; CI95% 7–99, respectively). Nordic hunting dogs had the highest (8.08; CI95% 3.55–16.7) and Chihuahueno the lowest cancer IRRs (0.42; 95%CI 0.31–0.57) compared to mixed breeds. In conclusion, the calculated IRs and IRRs revealed previously unknown predisposing factors, including novel breed-specific susceptibilities. The results may have implications for cancer screening, diagnostic work-up, breeding management and oncologic and translational research. [ABSTRACT FROM AUTHOR]

Simple Summary: Canine mast cell tumors are cutaneous and subcutaneous tumors that spread through the lymphatic system and lead to high mortality rates. Lymph node mapping, crucial for pinpointing the sentinel lymph node—the initial recipient of lymph from a tumor—is pivotal in diagnosing cancers that spread through the lymphatic system. Lymph node mapping is critical for assessing disease progression, guiding treatment, and predicting outcomes. Furthermore, the early detection of lymph node metastases is essential for improving prognosis. Lymph node mapping is a routinely applied diagnostic technique in humans but a relatively new technique in veterinary oncology; only recently have the first studies been conducted on its application in mast cell tumors. The primary aim of this article is to summarize the current knowledge on various lymph node mapping methods in canine mast cell tumors, highlighting their advantages, disadvantages, and the importance of this approach both for veterinary practitioners and dog owners. The sentinel lymph node exploits unique drainage patterns in mast cell tumors, highlighting the role of lymph node mapping in the precise diagnosis and treatment of canine mast cell tumors; the successful diagnosis of mast cell tumors could lead to significant progress in veterinary oncology. Cancer is the leading cause of death in companion animals. The evaluation of locoregional lymph nodes, known as lymph node mapping, is a critical process in assessing the stage of various solid tumors, such as mast cell tumors (MCTs), anal gland anal sac adenocarcinoma, melanoma, and mammary gland adenocarcinoma. MCTs are among the most prevalent skin malignancies in dogs. Staging is used to describe the extent of neoplastic disease, provide a framework for rational treatment planning, and evaluate treatment results. The aim of this review is to present the current knowledge on sentinel lymph node (SLN) mapping in canine MCTs, its influence on treatment decisions and prognosis, as well as the advantages and limitations of different SLN techniques currently available in veterinary oncology. A search methodology was adopted using the PubMed, Scopus, and Google Scholar databases. Critical analyses of up-to-date research have shown that lymphoscintigraphy can achieve a lymph node detection rate of between 91 and 100%. This method is becoming increasingly recognized as the gold standard in both human and veterinary medicine. In addition, initial studies on a limited number of animals have shown that computed tomographic lymphography (CTL) is highly effective in the SLN mapping of MCTs, with detection rates between 90 and 100%. The first study on contrast-enhanced ultrasound (CEUS) also revealed that this advanced technique has up to a 95% detection rate in canine MCTs. These methods provide non-ionizing alternatives with high detection capabilities. Furthermore, combining computed tomography and near-infrared fluorescence (NIR/NIR-LND) lymphography is promising as each technique identifies different SLNs. Indirect lymphography with Lipiodol or Iohexol is technically feasible and may be also used to effectively detect SLNs. The integration of these mapping techniques into routine MCT staging is essential for enhancing the precision of MCT staging and potentially improving therapeutic outcomes. However, further clinical trials involving a larger number of animals are necessary to refine these procedures and fully evaluate the clinical benefits of each technique. [ABSTRACT FROM AUTHOR]

Mast cell tumors (MCTs) are the most common skin tumors in dogs. Clinical data and cytological examination typically suffice for the initial diagnosis. However, prognosis and appropriate treatments necessitate histopathological examination. Amid global concerns regarding hazardous chemicals, the utilization of natural dyes has garnered increased attention. In this context, we focused on using butterfly pea flower (BPF) extract, rich in anthocyanins, as a dye for canine histopathological MCT staining. The dried petal powder was dissolved in distilled water (DW), filtered to obtain a crude extract, and then subjected to a freeze-drying process to preserve its quality. The BPF-dye was prepared by adding DW and 2.5% NaCl into the dried extract. The paraffin serial sections of 32 diagnosed MCTs were stained with the dye for 2 hours. Additionally, the sections were stained with Hematoxylin and Eosin, and Toluidine blue (TB) routine dyes for MCT diagnosis. Sections of non-MCT round cell tumors were also stained with BPF-dye. The results revealed pink-reddish specific staining in the neoplastic mast cell granules, with different staining levels corresponding to the degree of cytoplasmic granulation, similar to TB staining. However, TB staining exhibited blue or metachromasia, indicating differences in staining color. Additionally, the BPF-dye could differentiate MCT from non-MCT round-cell tumors, providing an alternative method of differentiation. The dye maintained its staining ability for 60 days when stored at 4oC. Accordingly, it holds potential as an alternative dye for MCT diagnosis, being locally available and eco-friendly. Further study should focus on improving the stability and longevity of the dye by preserving its anthocyanin content with natural co-pigments for practical application. [ABSTRACT FROM AUTHOR]

Here we report a case series of two dogs diagnosed as renal interstitial cell tumor (RICT) accompanied by elevated serum erythropoietin level and marked polycythemia. RICT is a rare tumor in dogs, originating from renal interstitial cells. While several renal tumors such as renal lymphoma, adenocarcinoma, carcinoma, sarcoma, fibrosarcoma and nephroblastoma may cause polycythemia, polycythemia caused by RICT has never been reported in dogs. The tumors in both dogs were solitary and lied within cortex or cortico-medullary junction. Histopathology revealed spindle-shaped cells suggesting mesenchymal origin, with no mitotic figures suggesting that the tumors in both dogs were benign. Following surgical removal of the affected kidney, serum erythropoietin level and polycythemia normalized in both dogs. [ABSTRACT FROM AUTHOR]

We describe two canine cases of cutaneous infection caused by Serratia marcescens. A 2‐year‐old castrated male mixed dog (Case 1) presented with multiple ulcerations on the dorsal trunk, which were observed 4 days after shampooing. A 4‐year‐old male wolf shepherd mix dog (Case 2) presented with ulceration and purulent discharge on the nasal bridge. Cytological examination of both cases revealed pyogranulomatous inflammatory cells with rod‐like infectious agents identified as S. marcescens in aerobic bacterial culture. Both patients were treated with oral antibiotics and topical chlorhexidine. Case 1 received enrofloxacin 10 mg/kg once daily for 1 week, followed by trimethoprim/sulfamethoxazole 15 mg/kg twice daily for 3 weeks. Case 2 received doxycycline 10 mg/kg twice daily for 4 weeks. No skin lesions were detected 2 weeks after the initial administration. The antibiotics were discontinued after a total 4 weeks of administration, and the skin lesions did not reappear. [ABSTRACT FROM AUTHOR]