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Feline histiocytic diseases are uncommon and rarely reported. Feline progressive histiocytosis (FPH) is the most common histiocytic disease in cats, predominantly affecting middle-aged animals. The most common presentation is the cutaneous form with solitary or multiple cutaneous nodules. A female, mixed-breed 6-year-old cat was presented with a 9-month history of a nodule in the nasal planum and was diagnosed by histopathology with histiocytic proliferation. At the time of diagnosis, new nodules were discovered on the lower lip, digit, and two lesions in the tail region, with the largest measuring 1.5 cm. Supplementary immunohistochemistry, showed immunolabeling for Iba-1 that in combination with the clinical course of the disease, confirmed the diagnosis of FPH. No response to chemotherapy treatment with lomustine alternated with doxorubicin was achieved. Toceranib phosphate resulted in a transient response and, stable disease for a short period (6 weeks). Electrochemotherapy with bleomycin was initiated and resulted in partial remission. Later on, chlorambucil was also started. Ultimately, the combination of all three treatments led to a complete response and disappearance of all the lesions. FPH is considered a disease resistant to various treatments, and effective treatments have not been reported. In this case report, we describe a successful multimodal therapeutic approach that resulted in complete resolution of the FPH and long-term survival (460 days without external lesions at the time of death). Further studies are necessary to confirm the efficacy of this therapeutic approach. [ABSTRACT FROM AUTHOR]

Background: Peripheral neuropathies result in sensory, motor or autonomic dysfunctions due to impairment of peripheral spinal or cranial nerves. Neoplasms such as lymphoma are cited as one of the many aetiological causes and it may affect the nerve directly, by compression, or indirectly (paraneoplastic) by remote action of the neoplasm located in an extra-neural site. This study aimed to report two cases of cranial nerve neuropathy (trigeminal and facial) associated with canine lymphoma, contributing to a better understanding of its paraneoplastic effects on the nervous system, as well as the diagnosis and treatment of these conditions. Cases: Two cases of canine lymphoma associated with possible signs of paraneoplastic peripheral neuropathy were attended at the Veterinary Hospital from the Universidade Federal de Minas Gerais (HV UFMG). Case 1. A spayed mixed breed bitch, with lethargy and unilateral exophthalmos. Brain computed tomography revealed a retrobulbar mass and cytology was diagnostic for extranodal lymphoma. Subsequent to computed tomography, the dog was presented with hypotrophy of the facial musculature and difficulty in grasping food, consistent with trigeminal nerve palsy, which resolved after institution of the 19-week chemotherapy protocol from the University of Wisconsin. Nevertheless, disease reccurred and a rescue protocol was initiated. Case 2. A female Dalmatian, spayed, was diagnosed with multicentric lymphoma, after cytology of the left mandibular lymph node. Chemotherapy was initiated with the same protocol of the previous case. However, the disease progressed and it was observed facial asymmetry with ptosis of the left eyelid, pina and lips, in addition to difficulty in grasping food, suggesting facial and trigeminal cranial nerve palsy. Clinical signs resolved after institution of a rescue chemotherapy protocol. However, in both cases, disease progression and poor clinical condition resulted in decision of euthanasia and necropsy was not authorized. Discussion: Canine lymphoma is often associated with paraneoplastic syndromes, with neuropathy being one of its possible clinical manifestations. In spite of that its pathogenesis remains unclear, with little information in the veterinary literature. Diagnosis is challenging and must be initially based on recognition of neurological clinical signs and lesion localization, as in the reported cases with lesions located on the fifth and seventh cranial nerves. In the patient from the first case, the absence of clinical signs and laboratory abnormalities suggestive of endocrinopathies, associated with neurological signs restricted to the trigeminal nerve, bilaterally, before starting chemotherapy and without the identification of brain lesions in computed tomography, suggested paraneoplastic involvement as the cause of neuropathy. In the second case described, the absence of clinical signs and laboratory abnormalitiess suggestive of endocrinopathies or nutritional deficiencies, associated with neurological signs restricted to the facial and trigeminal cranial nerves, suggested direct or indirect tumour involvement. Both cases showed improvement of neurological clinical signs after chemotherapy which favored the therapeutic diagnosis. Nevertheless, failure to authorize necropsy of patients made it impossible to confirm that peripheral neuropathy is secondary to the remote effect of lymphoma. [ABSTRACT FROM AUTHOR]

Background: Feline Injection Site-Associated Sarcoma (FISS) is a mesenchymal neoplasia of aggressive behavior that develops in sites where vaccine or drugs were administered. FISS is clinically characterized by the appearance of a solitary firm nodule or a diffuse mass, adhered to tissues, in regions associated to vaccine or drug applications. Despite low prevalence, tumor recurrence rates can reach 80%. FISS present more aggressive histological characteristics when compared to sarcomas not associated to injection sites. The aim of this paper is to contribute towards the understanding of the biological behavior of FISS. Materials, Methods & Results: Sixteen samples of FISS were analyzed. Fibrosarcomas were the most frequent histological subtype (62.5%). Malignant peripheral nerve sheath tumor was diagnosed in 18.75% cases. Ten (62.5%) FISS were classified as grade II; 4/16 (25%) grade I, and 2/16 (12.5%) grade III. Cox-2 overexpression occurred in 3/16 (18.75%) samples, with positive correlation between Cox-2 expression and cellularity (r = 0.696, P = 0.003). Mitotic index lower than 9 events was found in 11/16 (68.7%) samples and between 10 and 19 mitotic events in 5/16 (31.3%) cases. Mean Ki-67 expression was 2.39 ± 2.48%. FISS characterized as fibrosarcomas presented longer overall survival (median 545 days) than other histological subtypes (median 130.5 days) [P = 0.01]. Discussion: Patients with FISS generally present with larger nodules than those with sarcomas not associated to injections, suggesting a challenge for pet owners to note subcutaneous tumors in the interscapular region, in addition to the aggressive biological behavior of FISS. The influence of size on prognosis remains controversial. An association between histologic grade and the development of metastasis has been observed, with patients with grade III FISS associated with an increase in the metastatic rate. The present study did not find a correlation between overall survival and histologic grade. A positive correlation between the presence of giant multinucleated cells and tumor grade has been observed. Despite the absence of such correlation in the present study, possibly due to a small sample, a trend for higher frequency of giant cells in advanced histologic grade was observed. Cox-2 expression in 81.75% and overexpression in 18.75% of our samples contrasts with the 64% Cox-2 expression and the absence of Cox-2 expression found by other authors. A positive moderate correlation between cellularity and Cox-2 expression was also observed, while another study did not find a correlation of Cox-2 expression with tumor grade, recurrence rates or overall survival. Cox metabolites such as prostaglandins can enhance cellular proliferation, inhibit apoptosis, induce angiogenesis, alter cellular adherence to facilitate metastatic development and inhibit immune surveillance. In the present study, no correlation was found between Cox-2 and angiogenesis in FISS. Our findings demonstrated low immunolabeling for Ki-67. A previous study analyzed 52 samples of FISS, 51% of them considered grade III, with a mean Ki-67 labeling of 14%. The lower Ki-67 staining in the samples of the present study may be related to the lower number of samples of grade III FISS or to a difference in the studied population. Fibrosarcomas are associated with better prognosis than other histological subtypes. Furthermore, malignant peripheral nerve sheath tumors were diagnosed as a possible histological subtype of FISS. [ABSTRACT FROM AUTHOR]

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Targeted therapy of neoplasms is an emergent approach in human and veterinary medicine. Cyclooxygenase (COX) is a class of catalytic enzymes related to the formation of inflammatory mediators. COX-2 is expressed constitutively in a few body tissues, but it may be induced in specific pathophysiologic conditions, such as cancer. COX-2 expression in neoplams may be considered a potential predictive factor, due to the possible association of selective COX-2 inhibitors in adjuvant treatments. This scientific communication has the objective to report COX-2 expression in seven neoplasms of dogs and the usage of adjuvant treatment with COX-2 selective inhibitors as an effective and feasible option in cancer treatment. [ABSTRACT FROM AUTHOR]