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Background: Lipomatous tumors represent the most common type of soft tissue neoplasms. Mouse double minute 2 homolog (MDM2)/cyclin-dependent kinase 4 (CDK4) immunostaining is considered effective in differentiating between benign lipomas and intermediate malignant atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPSs). However, these tumors have traditionally been diagnosed histopathologically using hematoxylin and eosin-stained specimens, which is referred to here as morphological diagnosis. In this study, the accuracy of morphological diagnoses that had been made before MDM2/CDK4 immunostaining became available for distinguishing between lipoma and ALT/WDLPS was examined. Methods: The study participants were 109 patients with a morphological diagnosis of lipoma (68 patients) or ALT/WDLPS (41 patients) who had undergone surgical resection of the tumor in our hospital between 2009 and 2012. Tissue samples from all patients were used for MDM2/CDK4 immunostaining and the confirmation of MDM2/CDK4 amplification by fluorescence in situ hybridization (FISH). Results: Of the 41 patients with a morphological diagnosis of ALT/WDLPS, only 17 were positive for MDM2 FISH. In addition, one of the 68 patients with a morphological diagnosis of lipoma showed MDM2 amplification by FISH. When the definitive diagnosis of ALT/WDLPS was made by the positive results of MDM2 FISH, the sensitivity and specificity of morphological diagnosis were 41.5% and 98.5%, respectively. The sensitivity of MDM2 and CDK4 immunostaining was 55.6% and 40.0%, respectively, and their specificity was 87.0% and 84.6%, respectively. This indicates that the diagnostic accuracy of these immunostaining assays was not particularly high. The clinical features suggesting ALT/WDLPS were: patient age (older), maximum tumor diameter (large, cut-off value of 125 mm), tumor location (lower limb), and tumor depth (deep-seated). Conclusions: Morphological diagnosis alone can accurately diagnose lipomas. However, it has a propensity to overdiagnose ALT/WDLPS. Thus, MDM2 FISH should be used more proactively, not only for lesions with obvious morphological abnormalities, but also for lipomatous tumors that are clinically suggestive of ALT/WDLPS. [ABSTRACT FROM AUTHOR]

Hibernomas are rare brown fat tumors that garnered attention in the literature with the increasing use of [18F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography ([18F] FDG PET/CT) for the staging workup and follow-up of solid malignancies. Despite being benign tumors, they exhibit high metabolic activity due to their thermogenic nature, leading to significant radiotracer uptake on functional imaging. This can pose a challenge in differentiating them from the malignant lesions, especially the fat-containing malignancies such as liposarcoma. Hibernomas are typically found in the thigh, shoulder, back, and neck. Here, we present a unique case of Hibernoma in a patient undergoing PET/CT for melanoma follow-up in an unusual perihepatic location. To the best of the authors' knowledge, this represents the first reported case of a perihepatic hibernoma in the literature. The report also offers a literature review on hibernomas, including the influence of ambient temperature on their metabolism, diagnostic challenges, management strategies, and reports of hibernomas detected on functional imaging with a range of radiotracers. These observations could serve as a valuable clue in identifying hibernomas, potentially aiding in avoiding unnecessary biopsies or resections. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 44-year-old female with persistent knee pain following a twisting injury, leading to the identification of a popliteal lipoma as the source of her discomfort. Topics discussed include the role of musculoskeletal ultrasound in diagnosing soft tissue lesions, the management of posttraumatic knee osteoarthritis, and the use of physical therapy techniques to address knee pain and dysfunction.

Background: Intradural lipomas have been previously reported in individuals with spinal dysraphism; however, they have not been reported in cats with an intact spinal canal. Desmoid tumors are a rare finding in veterinary medicine, and there is no prior description of these tumors invading the spinal cord. Furthermore, the etiopathogenesis remains debated, with trauma, such as surgical intervention of an intradural structure, potentially contributing to its development. Case description: A 10-month-old domestic shorthair cat was presented initially with progressive proprioceptive ataxia. The MRI identified an intradural compressive lesion at the cranio-cervical junction, confirmed as a lipoma by histopathology. Despite surgical removal, postoperative complications led to the cat's euthanasia. Postmortem examination revealed invasion of a desmoid tumor at the surgical site. Conclusions: This case highlights the rarity of intradural lipomas in this location and the unusual complication of desmoid tumor invasion. It underscores the need for further research into the underlying mechanisms and potential diagnostic and therapeutic strategies for similar cases and suggests that these findings may be added to the list of potential post-surgical complications. [ABSTRACT FROM AUTHOR]

A 27-year-old female presented with persistent right medial plantar pain that developed over six months following an ankle sprain. The pain, described as sharp and radiating to the toes, progressively worsened, affecting her ability to walk. An initial ultrasound examination suggested medial plantar nerve compression by a lipoma, prompting her referral for ultrasound-guided hydrodissection. During the pre-procedure assessment, sono-palpation (palpation using the ultrasound transducer) localized the pain to the Master Knot of Henry—where the medial plantar nerve, artery, and flexor tendons intersect. No lipoma but a normal fat pad was observed. Ultrasound-guided hydrodissection with 5% dextrose mixed with lidocaine and saline was performed. After two sessions, her pain significantly decreased, with her visual analogue scale score dropping from 8 to 5 after the first session and to 2 after the second, allowing her to resume normal activities. This case highlights the value of ultrasound in accurately diagnosing and treating conditions involving the Master Knot of Henry. [ABSTRACT FROM AUTHOR]

Lipomas, benign adipose tissue tumors, are a common occurrence but currently, the options for their treatment are limited, with surgical excision being the most frequently used management pathway. This scenario can often lead to unsatisfactory cosmetic results and significant patient discomfort. This paper introduces a novel technique, percutaneous microwave ablation with liposuction, to address these challenges. The innovative procedure aims to enhance patient satisfaction, minimize post-operative discomfort, and improve aesthetic outcomes. The technique involves two key steps: (1) the application of percutaneous microwave ablation to selectively disrupt the lipoma cells, followed by (2) a targeted liposuction procedure to remove the ablated lipoma tissue. Our approach optimizes the removal of the lipoma and preserves the surrounding healthy tissue, reducing the risk of local recurrence and improving the cosmetic result. The use of preoperative ultrasound imaging allows for precise localization and delineation of the lipoma, aiding in the planning and execution of the procedure. This novel approach to lipoma treatment is reliable, associated with minimal morbidity, and consistently yields effective results. Additionally, it provides a new perspective on lipoma management, potentially changing the paradigm of current treatment approaches. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. [ABSTRACT FROM AUTHOR]

Background: Thymic pathologies represent the most common lesions of the anterior mediastinum. They may be classified as malignant or benign. Current diagnostic pathways recommend an initial assessment with computed tomography (CT) imaging to delineate potentially malignant thymic lesions. Despite this, high rates of non-therapeutic thymectomy continue to be observed. This carries with it significant anaesthetic, operative, and post-operative risks, in addition to healthcare costs. Consequently, there is a growing interest in magnetic resonance imaging (MRI) as a primary diagnostic modality for lesions of the anterior mediastinum. This narrative review outlines the current approaches to the evaluation of thymic lesions, with a discussion of the strengths and limitations of CT and MRI imaging modalities. It also evaluates the current discourse on the use of upfront MRI for thymic and anterior mediastinal lesion assessment. Methods: A narrative review was performed following a search on the Medline database. Articles that were evaluated had explored the role of MRI on the evaluation of thymic and anterior mediastinal lesions. Results: Current work-up for thymic and anterior mediastinal lesions are highly variable and centre around the use of CT. Upfront MRI demonstrates a similar accuracy to CT for various thymic and anterior mediastinal pathologies; however, the efforts to integrate this approach into routine practice remain in their infancy, with no standardised guidelines that exist. Conclusions: This narrative review demonstrates that there is a paucity of evidence relating to the sensitivity and specificity of MRI compared to CT for thymic lesion analysis and their subsequent relationship with non-therapeutic thymectomy. Future prospective trials to assess the role of MRI in thymic lesion determination are required to understand whether MRI can more accurately characterise these lesions to reduce non-therapeutic thymectomy. Additionally, further research efforts are required to characterise best-practice methods for integrating MRI into diagnostic pathways for these lesions in a cost-effective and resource-conscious manner. [ABSTRACT FROM AUTHOR]

Intramedullary spinal cord lipomas without spinal dysraphism are rare. Although they are benign tumors, they can cause significant neurological deficits. Their tight adherence to the spinal cord presents a challenge for resection. Therefore, we review our institutional experience treating adult patients with intramedullary lipomas in the absence of dysraphism and report long-term outcomes after resection. All adult patients undergoing resection of intramedullary spinal cord lipomas at a comprehensive cancer center between June 2011 and June 2023 were retrospectively identified. Patients with spinal dysraphism or extramedullary lipomas were excluded. Patients were included if they had microscopic surgical debulking with tissue sampling confirming the diagnosis. Six patients were identified with a mean age of 35.0 ± 11.5 years, and 67% were female. Four cases localized to the thoracic spine. Symptoms included pain, numbness, and lower extremity motor weakness; only one patient reported bowel and bladder dysfunction. All patients experienced transient neurological decline in the immediate postoperative period. Five recovered to independent ambulation at long-term follow-up, including one recovering to full strength. One patient required a repeat resection after four years due to tumor progression and functional decline. Tumor progression was not recorded in the other patients. Subtotal resection is a safe and effective treatment. Detethering of the spinal cord, resection of exophytic components, and tumor debulking can improve symptoms and prevent further deterioration in most cases. The resection can be assisted using a laser to vaporize the fatty tissue of the lipoma without physical manipulation of the spinal cord. [ABSTRACT FROM AUTHOR]

Objective To discuss the classification and surgical treatment strategies of complex spinal lipoma in children. Methods A total of 68 children with complex spinal lipoma were selected for treatment at Beijing Tsinghua Changgung Hospital, Affiliated Hospital of Tsinghua University from January 2015 to January 2023. They were divided into dorsal type (n = 42), transitional type (n = 15) and chaotic type (n = 11) based on XIU SUN classification. All patients underwent microsurgical treatment under neurophysiological monitoring. The early (within one month after surgery) and long-term (over one year after surgery) efficacy and safety of all patients were evaluated. Results Early efficacy: according to the Kirollos grading method for intraoperative decompression, 61 cases (89.71%) reached level -, 5 cases (7.35%) reached level -, and 2 cases (2.94%) reached level - ; according to the degree of resection, complete resection was achieved in 7 cases (10.29%), subtotal resection in 16 cases (23.53%), and partial resection in 45 cases (66.18%). Longterm efficacy: all patients were followed up for (5.00 ± 0.20) years. According to the McCormick spinal cord injury grading system, there was no statistically significant difference in the preoperative and postoperative neurological scores of the dorsal type (χ2 = 0.364, P = 0.549), transitional type (χ2 = 0.125, P = 1.000) and chaotic type (χ2 = 1.500, P = 0.219). MRI examination revealed recurrence of lipoma in 6 cases (8.82%). The postoperative symptoms improved to different degrees, and the progression free survivial rate was 91.18% (62/68). Postoperative complications: 25 cases(36.76%) of postoperative complications were observed, including urinary and fecal dysfunction in 13 cases (19.12%), decreased muscle strength in 9 cases (13.24%), cerebrospinal fluid leakage in 3 cases (4.41%), central nervous system infection leading to acute hydrocephalus in 2 cases (2.94%), with 2 cases presenting with both decreased muscle strength and urinary and fecal dysfunction. Conclusions XIU SUN classification has a guiding role in surgical strategy. In cases of dorsal type and most of transitional types, a subtotal or complete resection can be chosen. For chaotic type and medullary type, a reduction based approach is recommended. All types of spinal lipoma should undergo detachment release. [ABSTRACT FROM AUTHOR]

Lipoma is a benign tumor of well-differentiated adipocytes that has been reported in some domestic animals. Omental lipomas in human and domestic animals are rare and reported as a case report. This study aimed to report an omental lipoma in a slaughtered sheep. In the observational examination of a sheep in a slaughterhouse in Tehran Province, Iran, and during the inspection of the abdominal area, a mass was seen on the greater omentum. The mass was sampled and placed in 10% formalin for histopathology. The mass was single, soft, dense, capsuled, oval, weighing 150 g, and 4.5×3.5 cm in size. Microscopic examination showed omental mass composed of uniform and mature lipocytes encased within a thick layer of immature connective tissue. The final diagnosis was primary benign lipoma. Lipoma can occur anywhere in the body where there are fat cells, and probably obesity and trauma are important risk factors for its occurrence. The size of the lipoma mass may help predict the age of the mass. [ABSTRACT FROM AUTHOR]

Background: Caregivers are deeply concerned about children achieving independent walking, and evidence-based rehabilitation support is beneficial. However, current research is confined to a single study on spina bifida aperta, leaving a gap in understanding the timing of independent walking for lumbosacral lipomas. Objectives: This study aimed to examine the factors influencing independent walking in children with lumbosacral lipomas. Design: Retrospective cohort study. Methods: This retrospective cohort study included 124 children who underwent untethering surgery for lumbosacral lipomas. The age (in months) at which the children walked independently was used as the primary endpoint, and potential influencing factors, including the type of spinal lipoma, extent of lipoma removal, magnetic resonance imaging features, congenital anomaly complications, urinary/defecation management requirements, foot/toe symptoms, and orthotic device fabrications were analyzed. Results: Multiple logistic regression analysis showed that the most significant influencing factor for delayed independent walking was the presence of systemic combined anomalies (adjusted odds ratio = 15.5, P <.001), while non-systemic malformations, such as suburethral cleft, had limited effects. A subgroup analysis of 94 patients without systemic combined anomalies showed that the presence of a malformed conus medullaris was significantly associated with delayed independent walking (P =.014). The median age of independent walking in children with Morota's classification type 2 was 14 months, which is 1 month later compared to other types, although this difference was not significant (P =.055). Conclusion: Our findings suggest that complications arising from systemic combined anomalies and the presence of malformed conus medullaris are influencing factors in delays in independent walking in children with untethered lumbosacral lipomas. [ABSTRACT FROM AUTHOR]

Intravenous lipomas (IVLs) of the head and neck are uncommon benign tumors that develop within the venous walls, often detected incidentally during imaging for unrelated issues. While usually asymptomatic, these IVLs can cause congestive venous symptoms like swelling, paresthesia or pain in the head and neck and upper limbs, or even venous thromboembolism. The precise diagnosis of IVLs is predominantly achieved through computed tomography (CT) and magnetic resonance imaging (MRI), with CT being the most frequently used method. Symptomatic patients generally undergo open surgery with excision of the IVL followed by venous reconstruction, which has shown safe and effective outcomes. However, the management of asymptomatic IVLs remains controversial due to the limited number of reported cases. Despite this, there is a notable trend toward recommending surgical removal of IVLs to prevent complications and rule out malignancy, driven by the challenges of differentiating IVLs from malignant tumors using imaging alone. This review highlights the key differential imaging characteristics of IVLs and the main surgical techniques to remove the tumor and repair the vascular defect. Further research is necessary to establish a robust, evidence-based approach for treating asymptomatic IVLs, balancing the risks of surgery against the potential for future complications. [ABSTRACT FROM AUTHOR]

Objective: To improve the diagnosis and treatment of cervical lipoleiomyoma. Methods: 17 cases of cervical lipoleiomyoma admitted between September 2011 and April 2023 in the Beijing Obstetrics and Gynecology Hospital of Capital Medical University were analyzed retrospectively, including their pathogenesis, clinical characteristics, diagnosis and differential diagnosis, and treatment. Results: The average age of onset was (44.6 ±9.6) years. Patients mainly presented with lower abdominal pain or flank pain, menorrhagia, or asymptomatic. Ultrasound examination in all patients did not suggest cervical lipoleiomyoma, while 5 patients (29.4%) were suggested the degeneration of the myoma. Six patients underwent magnetic resonance imaging (MRI), and 2 cases detected fatty component. All 17 patients underwent surgical treatment. The cervical lipoleiomyoma ranged from 2.0 to 15.0 cm in diameter. Postoperative pathology of all cases showed cervical lipoleiomyoma. Follow-up ranged from 3 to 141 months, and only one patient had a cervical mass rediscovered at 9 months postoperatively and underwent radical surgery. Conclusions: Cervical lipoleiomyoma is a rare benign tumor, lacking specific clinical symptoms and imaging. The diagnosis mainly depends on surgical exploration and postoperative pathology, and surgery is the main treatment. Long-term follow-up after operation is required. [ABSTRACT FROM AUTHOR]

Myxolipomas are rare variants of lipomas characterized by abundant myxoid changes resulting from an abundant mucoid component. While myxolipomas have been reported in various anatomical locations, their occurrence in the popliteal fossa is exceptionally rare, with the last published case dating back to 1914. We present a case of a 64-year-old male with a large myxolipoma in the popliteal region. The patient underwent successful surgical excision, and a histopathological examination confirmed the diagnosis of myxolipoma. This case report highlights the clinical features, differential diagnosis, and diagnostic challenges associated with myxolipomas in the popliteal fossa. [ABSTRACT FROM AUTHOR]

Lipomas of the palatine tonsil are rare benign neoplasms in clinical practice. We present a case of palatine tonsillar fibroangiolipoma in a 50-year-old Chinese male with a history of multiple lipomas on the back and extremities. It was diagnosed based on histological examination and integrated analysis. Good wound healing and no evidence of recurrence were noted within 6 months follow-up after tonsillectomy. This article also puts a spotlight on the differential diagnosis of benign tonsillar tumors and reviewed recent relevant literature. [ABSTRACT FROM AUTHOR]

Background Soft tissue tumors are a diverse group of neoplasms that arise from the connective tissues, including muscles, fat, fibrous tissues, blood vessels, and peripheral nerves. These tumors can range from benign to malignant, and their accurate histopathological diagnosis is crucial for appropriate treatment planning and prognosis. The diversity in morphology and behavior of these tumors makes their histopathological evaluation both challenging and essential. Aim and Objectives The study aims to analyze the histopathological features of soft tissue tumors in order to classify them, determine their frequency, and correlate the findings with clinical parameters. Materials and Method This Observational study analyzed the histopathological records of patients diagnosed with soft tissue tumors over a period of one years at a tertiary care center. Specimens were obtained from surgical excisions and biopsies, followed by processing and staining using standard histological techniques. Tumors were classified according to the WHO classification of soft tissue tumors. Clinical data were reviewed, and correlations with histopathological findings were analyzed. Results A total of 60 cases of soft tissue tumors were reviewed, comprising 49 benign, 7 intermediate and 4 malignant tumors. The most common benign tumor was Adipocytic tumours, while the most frequent malignant tumor were undefferentiated. Histopathological analysis provided a definitive diagnosis in 95% of cases, with a significant correlation between histopathological findings and clinical presentation. Conclusion Histopathological analysis remains the gold standard for the diagnosis and classification of soft tissue tumors. Accurate histopathological evaluation is essential for effective clinical management and prognosis. [ABSTRACT FROM AUTHOR]

Lipomatous soft tissue tumors (STT), ranging from benign lipomas to malignant liposarcomas, require accurate differentiation for timely treatment. Complementary to MRI, Contrast-enhanced ultrasound (CEUS) is emerging as a promising tool, providing insight into tumor microperfusion in real-time. This study aims to explore the potential of preoperative CEUS in differentiating benign lipomatous tumors from malignant liposarcoma subtypes. Eighty-seven patients with lipomatous STT scheduled for surgery were enrolled. Clinical and MRI assessments were conducted to obtain general tumor characteristics. CEUS was used for a standardized tumor perfusion evaluation. Perfusion analysis included peak enhancement, rise time, wash-in perfusion index, and wash-out rate, reflecting the perfusion kinetics. Histopathological results were obtained for every STT and compared to perfusion characteristics. In total, 48 lipoma, 23 ALT and 11 liposarcoma were identified. Significant differences in tumor microperfusion were demonstrated, with higher perfusion levels indicating higher malignancy (Peak enhancement [a.u.] of Lipoma: 145 ± 238; ALT: 268 ± 368; Liposarcoma: 3256 ± 4333; p (ALT vs. Liposarcoma) < 0.001). A perfusion-based identification of a benign lipoma or ALT versus sarcoma resulted in a positive predictive value of 93%. Patient-related factors (age, gender, BMI, ASA score, smoking status) had no significant impact on the CEUS-based perfusion parameters. Our study suggests CEUS as a capable non-invasive tool for improving preoperative assessment of lipomatous STT. It can assist in the distinction between benign and malignant STT, accelerating treatment decisions and enhancing patient outcomes. Significant correlations between CEUS-derived parameters and malignancy highlight its risk assessment potential. [ABSTRACT FROM AUTHOR]

Congenital infiltrating lipomatosis of the face (CILF) is a benign non-epithelial tumor that was initially reported in 1983. Although lipomas are generally encased in fibrous tissue, CILF lacks a fibrous capsule and is characterized by intramuscular invasion. We herein report a case of CILF diagnosed based on the early eruption of permanent teeth and reviewed the English literature. The patient was a 5-year-old male with diffuse swelling of the left upper canine gingiva. He had undergone surgery at 3 years old to debulk left buccal lipoma. At presentation, facial asymmetry and diffuse swelling of the left cheek were noted. Radiographic examinations revealed the early eruption of and accelerated root formation by the left upper permanent teeth, bony hyperplasia of the left maxilla and zygomatic bone, and adipose hyperplasia of the left cheek region. Hormone examinations revealed no abnormalities. A histopathological specimen obtained from surgery to reduce buccal lipoma was re-evaluated and diagnosed as infiltrative lipoma. Based on histopathological and clinical features, the patient was diagnosed with congenial infiltrative lipoma was established. Conservative therapy was performed in consideration of future surgical interventions after adolescence. [ABSTRACT FROM AUTHOR]

Background: Lipomas are the most frequent neoplasm of mesenchymal origin in the head-and-neck region. Around 15% of lipomas are found in the head-and-neck region. The usual site where lipomas can be found in the head-and-neck region is in the posterior triangle of the neck but they can also be found in the anterior neck, infratemporal fossa, submandibular space, larynx, pharynx, and parotid gland. The incidence of parotid lipoma ranges from 0.6% to 4.4% of all parotid neoplasms. There are two histological variants, focal lipoma and diffuse infiltrating variant. We describe two cases of rare focal lipoma of the parotid gland, therefore, must be reported. As rare as it may appear, existing relevant literature suggest management to includes definitive radiological investigations such as magnetic resonance imaging (MRI) and complete removal of lipoma with or without a cuff of parotid tissue. Case Report: Two cases were identified with a parotid lipoma on final histology. Case 1 is a 57-year-old male with a history of painless left parotid swelling for 2 years, reported to be 5 cm × 4 cm size on ultrasound, therefore, underwent superficial parotidectomy. Case 2 is a 67-year-old male who presented with right parotid swelling for 15 years, reported on ultrasound to be 5 cm × 5 cm, and underwent excision of intraparotid tumor. He later went on to develop breast carcinoma. The facial nerve was intact of both patients. Conclusion: Parotid lipomas are rare entities that should be a differential for clinically soft parotid swellings. Management includes definitive radiological investigations such as MRI and complete removal of lipoma with or without a cuff of parotid tissue instead of regular ultrasound followed by fine-needle aspiration cytology. Although our cases were managed on the same regular outlines, but reporting these cases would suffice the potential role of MRI and computed tomography scan for parotid swelling as per existing literature. [ABSTRACT FROM AUTHOR]

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Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Lipomatous tumors represent the most common type of soft tissue neoplasms. Mouse double minute 2 homolog (MDM2)/cyclin-dependent kinase 4 (CDK4) immunostaining is considered effective in differentiating between benign lipomas and intermediate malignant atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPSs). However, these tumors have traditionally been diagnosed histopathologically using hematoxylin and eosin-stained specimens, which is referred to here as morphological diagnosis. In this study, the accuracy of morphological diagnoses that had been made before MDM2/CDK4 immunostaining became available for distinguishing between lipoma and ALT/WDLPS was examined. Methods The study participants were 109 patients with a morphological diagnosis of lipoma (68 patients) or ALT/WDLPS (41 patients) who had undergone surgical resection of the tumor in our hospital between 2009 and 2012. Tissue samples from all patients were used for MDM2/CDK4 immunostaining and the confirmation of MDM2/CDK4 amplification by fluorescence in situ hybridization (FISH). Results Of the 41 patients with a morphological diagnosis of ALT/WDLPS, only 17 were positive for MDM2 FISH. In addition, one of the 68 patients with a morphological diagnosis of lipoma showed MDM2 amplification by FISH. When the definitive diagnosis of ALT/WDLPS was made by the positive results of MDM2 FISH, the sensitivity and specificity of morphological diagnosis were 41.5% and 98.5%, respectively. The sensitivity of MDM2 and CDK4 immunostaining was 55.6% and 40.0%, respectively, and their specificity was 87.0% and 84.6%, respectively. This indicates that the diagnostic accuracy of these immunostaining assays was not particularly high. The clinical features suggesting ALT/WDLPS were: patient age (older), maximum tumor diameter (large, cut-off value of 125 mm), tumor location (lower limb), and tumor depth (deep-seated). Conclusions Morphological diagnosis alone can accurately diagnose lipomas. However, it has a propensity to overdiagnose ALT/WDLPS. Thus, MDM2 FISH should be used more proactively, not only for lesions with obvious morphological abnormalities, but also for lipomatous tumors that are clinically suggestive of ALT/WDLPS.

Lipomas are one of the most common mesenchymal tumors in the human body, exhibiting a heightened prevalence between the ages of 40 and 60 years. However, primary intraoral lipomas are rare. Myxoid lipoma, which is characterized by abundant mucoid components, is a particularly rare histological subtype of lipoma. This study presents two cases of myxoid lipoma that occurred outside the common age range for occurrence, one in the right submandibular area of a 67-year-old male and the other in the lower lip of a 3-year-old child. Through these case reports, the aim was to introduce myxoid lipoma, a rare subtype affecting facial areas, and provide a brief review to assist in the differential diagnosis, emphasizing the importance of pathological assessment. Even in age groups and anatomical locations not typically associated with lipomas, it is crucial to emphasize the necessity of careful evaluation.

Lipomas are superficial tumors that occur primarily in the subcutaneous region and very rarely occur deeply within or between the muscle layers. No reports to date have described cervical lipomas in patients with head and neck cancer who underwent neck dissection. We herein report a case involving a 72-year-old woman with supraglottic carcinoma complicated by a cervical lipoma who underwent simultaneous neck dissection and lipoma removal. The lipoma was a deep-seated intermuscular lipoma arising in the longus cervicis muscle. We initially considered that the lipoma would be removed en bloc with neck dissection, but the imaging findings clearly indicated that the tumor was located more deeply than the prevertebral layer of the deep cervical fascia and outside the range of neck dissection. The lipoma was removed by incision of the prevertebral fascial layer following neck dissection, and no complications occurred.

Lipomas, benign tumours of mature fat cells, typically appear in the head-and-neck region, with rare occurrences in the mouth. This case involves an unusually large intraoral lipoma exceeding 1.8 cm. Lipomas, usually painless, may go unnoticed for an extended period. Recognition of atypical presentations is crucial for accurate diagnosis and management. A surgical procedure under local anaesthesia removed a 1.8 cm × 1.7 cm × 1.3 cm gingival growth. Using a 15 No, an incision was made on the BP blade to preserve the attached gingiva. Coe-Pak dressing safeguarded the treated area, ensuring optimal recovery. The soft-tissue section’s histopathological examination revealed an encapsulated lesion with mature adipocytes arranged in lobules, separated by fibrous connective tissue. Adipocytes displayed polygonal shapes with clear cytoplasm, eccentrically placed nuclei and compressed membranes. Deeper observations included dilated blood capillaries, extravasated red blood cells, muscle fibres and minimal inflammatory cells. Lobules of mucous salivary acini were also identified as intraoral lipomas, rare but detected during dental check-ups. They usually lack pain, which causes delayed treatment. Patients focus on aesthetics or mild discomfort. Clinicians must use modern diagnostics to identify and conservatively manage intraoral lipomas. Ongoing trials explore non-surgical treatments, potentially shaping future standards of care.

Intussusception is a rare condition in adults that occurs when a segment of the bowel telescopes into the lumen of the more distal segment. Colocolic intussusception accounts for only 8.3-38% of all intussusception cases in adults, the majority due to malignant causes such as adenocarcinoma, lymphoma, leiomyosarcoma, undifferentiated carcinoma... Lipoma is the most common benign cause, followed by gastrointestinal stromal tumors and adenomatous polyps. Surgery is the recommended treatment for colonic lipoma-induced intussusception. In this report, we describe a rare case of a 52-year-old female patient with colocolic intussusception due to an ascending colon lipoma which was diagnosed by ultrasound and computed tomography.

Angiomyxomas, also known as vascular myxolipomas, are a rare type of soft tissue tumor characterized by the proliferation of adipose tissue within a myxoid stroma accompanied by multiple vascular channels. They represent a distinct variant of lipomas and require differentiation from other benign and malignant lipoma subtypes. Despite their rarity, only a few cases of angiomyxolipoma have been documented in medical literature. We present a case of angiomyxolipoma occurring in the cheek of a 40-year-old female patient who presented with a long-standing history of swelling on the left side of her face. Histopathological examination revealed alternating nests of myxoid and adipose tissue containing dilated blood vessels, which confirmed the diagnosis of angiomyxolipoma. This case underscores the importance of recognizing and accurately diagnosing rare soft tissue tumors like angiomyxolipoma to guide appropriate management and follow-up care. [ABSTRACT FROM AUTHOR]

Hibernoma is a relatively uncommon benign neoplasm of brown adipose tissue which usually affects head and neck region, thigh and rarely breast. There are different subtypes of hibernoma with the spindle cell-type is the least common one. Herein, we are reporting a case of this rare spindle cell hibernoma in a location which has not been previously reported: perinephric adipose tissue. This tumor was presented as a renal mass on imaging. [ABSTRACT FROM AUTHOR]

Introduction: Small bowel bleeding is being diagnosed with increasing frequency with the development of capsule endoscopy. Case Presentation: We report a case of lipoma that caused hematochezia in an 80-year-old woman with ischemic heart disease receiving antiplatelet therapy and on hemodialysis for renal failure. Contrast-enhanced computed tomography scans, esophagogastroduodenoscopy, and colonoscopy failed to identify the source of hematochezia. Capsule endoscopy revealed a small bowel tumor, which was removed through laparoscopic surgery without interruption of antiplatelet agents. The small bowel tumor was pathologically diagnosed as a lipoma. There was no recurrence of the hematochezia after surgery. Conclusion: Lipomas could cause hematochezia. With appropriate preoperative testing, comorbidity assessment, and surgical planning, we believe that surgical resection is a safe treatment option for the removal of small bowel lipomas even in patients who are on hemodialysis or are taking antiplatelet agents.

Intra-articular lipomas are infrequently reported, with most reported cases occurring in the knee joint. A case of intra-articular lipoma in the small joints of the hand, specifically in the pisotriquetral joint, has been documented for the first time. A 24-year-old male visited the emergency department after a road traffic accident with a painful and swollen wrist. Radiographic examination revealed fractures of the distal radius and triquetrum. A subsequent wrist computed tomography scan identified an intra-articular lipoma within the pisotriquetral joint, further confirmed by ultrasonography. This article underscores the importance of recognizing that, though exceedingly rare, intra-articular lipomas should be considered in the differential diagnosis of soft-tissue tumors affecting the hand and wrist.

Background: Myelolipoma is an uncommon benign tumor composed of mature adipose tissue and hematopoietic elements. These tumors generally affect the adrenal glands, with anomalous presentations being rare and with few cases described in the literature. Most myelolipomas are asymptomatic and discovered incidentally, either through imaging tests or at autopsies. However, depending on the location and size of the lesion, myelolipomas can cause symptoms of mass effect. This article aims to report a very rare presentation of a symptomatic primary myelolipoma affecting the ribs. Case presentation: A 21-year-old white female patient presented with a complaint of burning chest pain over 3 months, with gradual worsening in intensity, accompanied by a progressively growing bulge in the right thoracic wall. The patient underwent thoracotomy of the fifth and sixth ribs with complete excision of the lesion with a safety margin. Thoracic wall reconstruction was performed using a polypropylene mesh. The patient had a good postoperative course and was discharged on postoperative day 3. Histopathological examination revealed a histological image consistent with myelolipoma. Conclusions: This report underscores the importance of considering a myelolipoma diagnosis for tumor masses in the ribs. [ABSTRACT FROM AUTHOR]

Introduction/Objectives: Neck lumps are a common presentation to primary care services. The aetiology of posterior neck lumps is poorly explored in the literature, and therefore remain a concern to patients and clinicians. This often results in an urgent referral for ultrasound assessment. The authors of this study sought to evaluate the aetiology of posterior neck lumps from a radiological perspective, to assess whether ultrasound can be used as a useful adjunct, rather than a first-line urgent investigation. Methods: A retrospective case series was carried out, examining all primary care referred ultrasound studies for assessment of posterior neck lumps, performed at a single institution in Essex, United Kingdom, over a period of over 10 years dating between 2nd February 2012 to 8th November 2022. Data was collected on: patient age at the time of study, patient sex, whether the lump was single or multiple as palpated and documented by the primary care physician, size of the lump to the nearest 0.5 cm as documented on ultrasound using the longest dimension, sonographic diagnosis and any follow up imaging (not limited to ultrasound). Results: A total of 623 neck ultrasounds were performed on 615 adults. Of the overall radiological diagnoses made from the 623 scans, 555 (89.09%) scans were benign, 63 (10.11%) scans had no lump found on sonography, and 3 (0.48%) scans showed malignancy. In the remaining 2 (0.32%) scans, the lump was deemed indeterminate. The most common aetiologies for benign lumps were due to: normal lymph nodes (n = 263; 42.21%), lipomas (n = 152; 24.39%), and benign dermal cysts (n = 105; 16.85%). All 3 malignant cases had co-existing anterior and posterior neck lumps. Conclusions: Given that the overwhelming majority of posterior neck lumps in our study had benign findings, we propose that patients with solitary or even multiple posterior neck lumps alone, regardless of size can either be investigated routinely or can be reassured depending on other clinical examination characteristics. Patients who have the presence of co-existing anterior and posterior neck palpable neck lumps justifies urgent or 2-week wait radiological investigation. [ABSTRACT FROM AUTHOR]

Adrenal myelolipoma is a rare benign tumor which consists of mature adipose tissues and hematopoietic tissues in variable proportion. These tumors are mostly detected incidentally on imaging done for other reasons but due to advancement in non-invasive imaging modalities they are found more frequently now. The incidence of adrenal myelolipoma is found to be 0.08 to 0.4%, whereas they constitute 15% of all adrenal incidentalomas. Usually, these tumors are small, unilateral, and hormonally inactive, arising from adrenal gland, but there are articles that have reported about giant, bilateral, extra-adrenal, or hormonally active myelolipomas. Here, we present a unique case of right adrenal myelolipoma with an unusual presentation as the patient was in the 2nd decade of life (24 years old) and the tumor weighed 5 kg which was successfully managed by right adrenalectomy. Further, we have reviewed the articles published in Indian literature. [ABSTRACT FROM AUTHOR]

Objective: Although lipomas are the most common benign soft tissue tumors, they are rarely found in the hand and are exceptionally rare on the fingers. Therefore, the purpose of this study was to investigate lipomas in atypical locations to aid in the differential diagnosis of finger tumors. Methods: We retrospectively examined a cohort of 20 patients who were diagnosed with lipomas on the fingers. The diagnosis was made through clinical and imaging examinations. Surgical intervention was based on symptoms such as pain, paresthesias, functional impairment, or aesthetic concerns. Results: Lipomas were more likely to be located on the third finger of the right hand, and most common pathological subtype was fibrolipoma. One giant lipoma was observed. Conclusion: Lipomas on the fingers are rare occurrences that typically affect females, and the optimal surgical treatment involves complete removal of the tumor to achieve definitive healing. Despite their rarity, clinicians should consider lipomas in the differential diagnosis of soft tissue tumors in the hand. [ABSTRACT FROM AUTHOR]

Purpose: Differentiating benign lipomas from malignant causes is challenging and preoperative investigative guidelines are not well-defined. The purpose of this study was to retrospectively identify cases of head and neck lipomas that were surgically resected over a 5-year period and to identify the radiological modality chosen and features discussed in the final report. Multidisciplinary outcomes and pathology reports were examined with a view to identifying high risk features of a lipoma to aid in future risk stratification. Methods: Retrospective chart review of pathology characteristics, radiological features (modality, size, calcifications, septations, globular/nodular foci), multidisciplinary discussion and history of presenting complaint was performed. Results: Two liposarcomas and 138 lipomas were identified. Twenty-two percent of all lipomas received radiological investigation. Twenty-two percent of imaging referrals were possibly inappropriate. Furthermore, radiological features suggestive of malignancy were not present in the final radiology report, X2 = 28.8, p < 0.0001. Conclusion: As expected, the incidence of liposarcoma is low. There is limited awareness of radiology referral guidelines superimposed with a tendency to over-investigate lipomas. Furthermore, radiological features suggestive of malignancy were inconsistently reported on and not documented in multidisciplinary discussions. Therefore, we propose a multidisciplinary checklist for referring physicians and radiologists to aid in diagnostic work-up. [ABSTRACT FROM AUTHOR]

Introduction: Intraosseous lipomas (IL) are rare benign neoplasms of bone which very rarely occur in the facial bones such as the mandible. Of the documented cases, many are often asymptomatic and consequently, are an incidental finding discovered by the practitioner. Case Report: The following case report recounts a 22‐year‐old patient referred for extraction of a carious molar at an Oral and Maxillofacial unit with an incidental finding of pathology involving the contralateral lower left wisdom tooth (LL8) on radiographic examination. Further investigations showed associated external root resorption of the lower left wisdom tooth and a provisional diagnosis of a radicular cyst was made. The case was managed by extracting the associated tooth and enucleating the lesion. During the procedure, fatty tissue was curetted at the apex instead of the expected cystic content. Subsequent histopathology confirmed the diagnosis of an IL. Conclusion: To the authors' knowledge, this is only the second documented case of an IL associated with tooth resorption. Findings from this case further our knowledge of the relatively uncommon pathology of intraosseous lipomas in the mandible and highlight the need for histopathological documentation and reporting of apical lesions. [ABSTRACT FROM AUTHOR]

Lipomas are common benign adipose tissue tumors but are infrequently found in the labia majora, especially at a large size. We report a case of a giant lipoma of the labia majora in a 37-year-old woman diagnosed by imaging methods and successfully treated by surgery. This case highlights the importance of considering lipoma in the differential diagnosis of labial masses and underscores the role of imaging in diagnosis. They need to be differentiated from liposarcoma or omental herniation into Nuck's canal. It also demonstrates the effectiveness of surgical management for large lipomas in sensitive areas, with attention to both medical and aesthetic outcomes. [ABSTRACT FROM AUTHOR]

Mediastinal myelolipoma is a rare condition and has no obvious symptoms. In the past 20 years, some clinical cases have been documented. However, the literature has not systematically summarized its imaging features. The aim of this paper is to present a case of right posterior mediastinal myelolipoma and to review and summarize its imaging features. Twenty-six articles were included in our study, which included a total of 26 patients and 33 lesions; 90.9% of the lesions were located in the mediastinum at the level from the 8th thoracic vertebral body to the thoracic 12th vertebral body. Among the cases with unilateral mediastinum, 68.4% of the cases were located in the right posterior mediastinum. Bilateral lesions accounted for almost one-fourth of all lesions. After contrast medium was injected, 93.9% of the lesions had mild to moderate enhancement; 84.8% of the lesions contained fat density; and 75.8%, 69.7%, 87.9%, and 75.8% of the lesions showed clear boundary, regular shape, heterogeneity and were encapsulated, respectively. Only 12.1% of the lesions contained calcification. An inhomogeneous mass in the right posterior mediastinum near the spine, including fat density, is the predominant imaging marker of most mediastinal myelolipomas. [ABSTRACT FROM AUTHOR]

Lipoleiomyoma is relatively rare, and even rarer to appear in the uterus and extrauterine at the same time. We report a case of multiple lipoleiomyoma of uterine and extrauterine. The patient was suggested the possibility of a teratoma of the right ovary, and recommended laparoscopic exploratoration. A right posterior uterine wall inter teratoma muscular exophytic nodule, a solid mass at the end of the appendix and a solid peritoneal mass in the posterior wall of the bladder were found during operation. Postoperative histological pathology and immunohistochemistry showed the lipoleiomyoma. Lipoleiomyoma is a rare benign tumor, mostly in the uterus. The occurrence of extrauterine lipoleiomyoma may be attributed to implantation after gynecological surgery. Clinical symptoms of uterine and extrauterine lipoleiomyoma are atypical. As the fat within the mass can be detected on imaging examination, especially when the mass is adjacent to the adnexal, it is more likely to be misdiagnosed as ovarian teratoma. MRI should be performed if necessary, to improve the detection rate. The treatment of uterine and extrauterine lipoleiomyoma is mainly surgical resection, with a good prognosis. There is a risk of malignant transformation or coexistence with other gynecological malignancies, so the long-term postoperative follow-up is required. [ABSTRACT FROM AUTHOR]

Tumors may be responsible for up to 5% of trigeminal neuralgia cases. Predictors of long-term pain relief after surgical resection of various cerebellopontine angle tumor types are not well understood. Previous studies found that size and extent of resection predict long-term pain status, although resection of tumor involving the trigeminal ganglion may be associated with high morbidity. This study evaluated predictors of TN pain freedom after resection of a nonacoustic CPA tumor, with avoidance of any portion involving the TG. In a retrospective cohort study, we evaluated clinical outcomes and complications after surgical resection of nonacoustic CPA tumors with purposeful avoidance of the TG causing trigeminal neuralgia. The primary outcome was pain-freedom. We performed logistic regression analyses to examine the relationship between pain-freedom at last follow-up and age, side of symptoms, preoperative symptom duration, tumor diameter, tumor type, and concurrent neurovascular compression (NVC). Of 18 patients with nonacoustic CPA tumors causing TN treated with surgical resection, 83.3% were pain-free at last follow-up (mean 44.6 months). Age (P = 0.12), side (P = 0.41), preoperative symptom duration (P = 0.85), tumor diameter (P = 0.29), tumor type (P = 0.37), and NVC presence (P = 0.075) were not associated with long-term pain freedom. This study provides additional evidence that various tumor types causing TN may safely undergo surgical resection and decompression of the trigeminal nerve to treat TN. This study presents a cohort of patients that underwent resection of a nonacoustic CPA tumor, with purposeful avoidance of the TG to minimize complications, demonstrating high rates of long-term pain freedom. [ABSTRACT FROM AUTHOR]

Persistent lymphocele of the groin is a complication of groin surgery that can severely impact the quality of life. The restoration of the interrupted lymphatic pathway is considered by many authors the ideal treatment to prevent a recurrence. However, multiple aspiration procedures and surgical revisions can compromise the availability of local veins needed for a lymphovenular bypass surgery. In addition, surgical debridement of a long-standing lymphocele can generate extensive dead space and contour deformity. A flap delivering additional venules for trans-flap lymphovenular anastomoses (LVAs) can overcome both problems by providing soft tissue and competent veins harvested outside the zone of injury. A successful case of severe groin lymphocele treated with trans-flap LVAs from an abdominal-based flap is presented. The patient was referred to us for a recurrent lymphocele developed in the right groin after lipoma excision that persisted despite multiple surgical attempts. After the identification of patent and draining inguinal lymphatic vessels, a pinch test was used to design a mini-abdominoplasty superficial inferior epigastric artery flap. The superficial veins of the cranial incision were identified and anastomosed to the lymphatic vessels after the pedicled flap harvested and insetted in the groin. The early restoration of lymphatic drainage and the optimal aesthetic outcome supports the combined approach offered by trans-flap LVAs as a valuable therapeutic option for severe and persistent lymphocele. [ABSTRACT FROM AUTHOR]

Intra-articular lipomas are infrequently reported, with most reported cases occurring in the knee joint. A case of intra-articular lipoma in the small joints of the hand, specifically in the pisotriquetral joint, has been documented for the first time. A 24-year-old male visited the emergency department after a road traffic accident with a painful and swollen wrist. Radiographic examination revealed fractures of the distal radius and triquetrum. A subsequent wrist computed tomography scan identified an intra-articular lipoma within the pisotriquetral joint, further confirmed by ultrasonography. This article underscores the importance of recognizing that, though exceedingly rare, intra-articular lipomas should be considered in the differential diagnosis of soft-tissue tumors affecting the hand and wrist. [ABSTRACT FROM AUTHOR]

Though they are commonly known as "universal tumors," lipomas are rarely found in the vulva. In this report, we discuss the case of a 15-year-old girl who presented with an enormous (26.5 × 21.5 × 6.5 cm) left labial swelling that had been progressively enlarging for a year and had led to extensive distortion of the vulvar anatomy. Following imaging, surgical excision with vulvar reconstruction was performed focusing on esthesis and function. Pathological examination confirmed the clinical and radiological diagnosis of a lipoma. The patient is doing clinically well at 1 year of follow-up with significant improvement in her academic performance and self-esteem. [ABSTRACT FROM AUTHOR]

Rectal signet ring cell carcinoma represents a rare subtype of colorectal adenocarcinoma known for its aggressive biological nature and poor prognosis. Although the co-occurrence of colorectal carcinoma with other tumors has been reported, the uncommon phenomenon of tumor-to-tumor metastasis, first described in 1930, remains rare. The most frequent donor neoplasms are lung or breast carcinomas, whereas cerebral meningiomas have been reported to be the most frequent recipient neoplasms. Here we report a case of a typical lipomatous tumor harboring metastatic signet ring cell rectal carcinoma. It is about a 42-year-old man diagnosed with rectal signet ring cell carcinoma and treated with concurrent radiotherapy and chemotherapy followed by an anterior resection and manual coloanal anastomosis with a temporary ileostomy. During the surgery, an abdominal wall lipoma was discovered and excised. A histopathological examination revealed infiltration of the fibro adipose tissue by a mucinous adenocarcinoma with a contingent of signet ring cells. The patient died 12 months after adjuvant chemotherapy due to peritoneal progression. To the best of our understanding, this represents the initial documented instance of tumor-to-tumor metastasis from rectal signet cell carcinoma to a conventional nonvascular lipoma. Consequently, even if one of these tumors appears clinically and radiologically benign, it is prudent to entertain the prospect of tumor-to-tumor metastasis. Thus, a comprehensive pathologic study of both tumors is highly recommended. [ABSTRACT FROM AUTHOR]

Intramuscular lipomas, typically found in subcutaneous tissue, rarely affect deeper muscular planes, especially those of the head and neck region. The following are 3 cases of intramuscular lipomas involving the sternocleidomastoid muscle. The first 2 patients presented with painless, palpable masses confirmed by diagnostic imaging as well-circumscribed intramuscular lipomas. One was treated surgically, while the other was managed conservatively with monitoring and close follow-up. The third patient reported dysphagia associated with occasional dyspnea and mild pain. The mass was identified as infiltrative lipoma and was resected surgically. Complete tumor removal with no recurrence at 6 months was observed for the first and last cases. The second case was serially followed at 3 and 6 months with no interval changes. We report the largest case series on intramuscular lipomas of the sternocleidomastoid muscle to enhance our understanding of this rare entity. [ABSTRACT FROM AUTHOR]

This study aimed to assess the imaging features of atypical lipomatous tumors (ALTs) and lipoma with fat necrosis. This study included patients with histopathologically proven fat necrosis within adipocytic tumors who underwent preoperative imaging. Magnetic resonance imaging (MRI) and/or computer tomography (CT) findings of fat necrosis associated with lipomatous tumors were retrospectively reviewed, emphasizing the "fatty island sign (FIS)." FISs were defined as well-demarcated, focal fat-containing areas surrounded by more thickened septa compared with other intratumoral septa. Imaging findings of FIS were compared between ALT and lipoma. Fat necrosis was histopathologically confirmed in 17 patients (6 ALTs and 11 lipomas). Among them, 18 FISs were observed in 10 lesions (59%). Multiple FISs within a lesion were observed in 4 (40%) patients. The median maximum diameter of the FISs was 37 mm. Hypointense areas within FISs relative to the subcutaneous fat on T1- and T2-weighted images were observed in 8 (80%) and 9 (90%), respectively, whereas hyperintense areas within FISs on fat-suppressed T2-weighted images were observed in 2 (20%). Nonfatty solid components within FISs were observed in 2 (20%). On CT, increased fat attenuation and pure fat attenuation within FISs were observed in 6 (86%) and 1 (14%), respectively. The imaging findings of FIS were not significantly different between ALT and lipoma. FISs were observed in 59% of the histologically proven ALT and lipoma patients with fat necrosis. The hypointense areas relative to the subcutaneous fat on T1- and T2-weighted images and increased fat attenuation on CT were usually observed within FISs. • Fatty island sign (FIS) was observed in 59% of lipomatous tumors with fat necrosis. • FIS was defined as a focal fat-containing area surrounded by thickened septa. • FIS was observed in both atypical lipomatous tumors (ALTs) and lipomas. • Hypointensity within FIS relative to fat was usually observed on T1WI and T2WI. • Radiologists need to differentiate ALT from lipoma in areas excluding FISs. [ABSTRACT FROM AUTHOR]

A scoping search of the literature review found 30 clinical or clinical research articles on spontaneous mammary neoplasms in guinea pigs between 1908 and 2023. Despite the many reports, only 4 described tumor biological behavior and/or the presence of metastases. This retrospective study collected data on the tumors found in guinea pigs' mammary/inguinal regions. Both mammary and mesenchymal (lipomatous) neoplasms were seen. Survival time after diagnosis of a neoplasm was evaluated. For mammary neoplasms, risk factors, such as age and sex, and prognostic factors, such as neoplasm malignancy and the effect of surgery on survival, were investigated. Medical records of guinea pigs with mammary/inguinal neoplasms between 2006 and 2022 from 3 Parisian veterinary referral hospitals and 1 French diagnostic pathology laboratory were reviewed. Eighty-five (77%) guinea pigs had mammary neoplasms, and 25 (23%) had lipomatous neoplasms. A logistic regression model highlighted that males have significantly increased odds of malignant mammary neoplasms than females, while females (85%) are often found to have benign mammary neoplasms. Malignancy was significantly associated with aging. Older animals had greater odds of having malignant neoplasms than young animals. The mean age at diagnosis for mammary/inguinal lipomas was 3.0 years, while a benign mammary neoplasm was 3.1 years, and a malignant mammary neoplasm was 4.2 years. The survival prognosis was not influenced by the histopathological diagnosis of malignant versus benign neoplasm or the surgical technique (mastectomy vs lumpectomy) to treat the mammary neoplasm. The median survival time after diagnosis of a mammary neoplasm was 1.2 years, and for an inguinal lipoma was 3.0 years. Twenty-three percent of neoplasms in the mammary/inguinal region are lipomatous. Male guinea pigs usually have a malignant mammary neoplasm, while females mostly have a benign one. Malignancy is typically seen in older animals. In this dataset, survival time was unaffected by malignant versus benign neoplasm diagnosis or surgical treatment. The survival analysis results should be considered with caution in light of the small sample size. [ABSTRACT FROM AUTHOR]