Expression of programmed cell death protein 1 and programmed cell death ligand 1 in feline injection site fibrosarcomas.

Feline injection site fibrosarcomas represent a unique challenge in veterinary oncology due to their association with injection sites and aggressive behaviour. The study explores the expression of immune checkpoints programmed cell death protein 1 and programmed cell death ligand 1 in the malignancy, aiming to unravel their potential significance in tumour progression. The study included 31, archival diagnostic specimens of feline fibrosarcomas, located in the common injection sites. The programmed cell death protein 1 and programmed cell death ligand 1 expression in tumour cells and tumour infiltrating lymphocytes were assessed by immunohistochemical methods. Programmed cell death protein 1 and programmed cell death ligand 1 expression were observed in 84% and 81% of cases, respectively. In tumour infiltrating lymphocytes the PD-1 expression was observed in 71% of cases. Notably, higher programmed cell death protein 1 expression correlated with tumour grade and heightened inflammation score, suggesting a potential association with tumour aggressiveness. Similarly, programmed cell death ligand 1 expression exhibited a positive correlation with tumour grade and inflammation score. The observed findings suggest a potential role for programmed cell death protein 1 and programmed cell death ligand 1 in tumour progression and immune response within the tumour microenvironment. Moreover, this study contributes to a deeper understanding of feline injection site fibrosarcoma pathogenesis, emphasizing the importance of considering immunological perspectives in developing effective treatment strategies for this challenging condition. Further investigations are warranted to advance our knowledge and refine therapeutic approaches for feline injection site fibrosarcoma management.

First report of spontaneous hepatic fibrosarcoma in a white-tufted marmoset (Callithrix jacchus) kept in captivity.

Reports of sarcomas in nonhuman primates are scarce and, specifically, primary hepatic sarcomas are rare, as in humans. This is the first report of an aggressive hepatic fibrosarcoma in a young adult Callithrix jacchus. The final postmortem diagnosis was obtained by means of immunohistochemical analysis, which confirmed the tumor histogenesis.

Histological observations on aural fibrosarcoma in a Holstein cow.

Fibrosarcomas occur as a mesenchymal tumour of malignant fibroblasts in a collagen background and are usually found in the female genital organs and rarely involve the skin. A 5-year-old female Holstein cow with a raised mass at the base of right ear was referred. On gross examination, the mass was approximately 13.00 × 10.00 × 7.00 cm in size. Finally, complete surgical removal was selected. The mass was encapsulated and the dermis was expanded by spindle-shaped to polygonal neoplastic cells. These cells were arranged in interwoven pattern. Mitotic figures were infrequent. Masson's trichrome demonstrated the positive and blue staining of collagen. Immunohistochemically, the sections were uniformly positive for Vimentin and negative for Desmin, SMA and GFAP. A well-differentiated fibrosarcoma was diagnosed based on histopathological features. Surgical excision is the treatment of choice for this neoplasm. In the present case, surgery was also performed successfully and no new growth of the mass was observed 4 months following the surgical procedures. To our knowledge, this is the first report of well-differentiated fibrosarcoma in a Holstein cow.

Metallothionein expression in feline injection site fibrosarcomas.

BACKGROUND: Feline injection site fibrosarcoma is an aggressive and infiltrative tumour arising in the background of chronic inflammation. The aim of this study was to evaluate the expression of metallothionein (I-II) in feline injection site fibrosarcomas and to assess its possible relationships with Ki67 index, inflammation score and tumour grade. The study included 40 feline fibrosarcomas, located in the common injection sites (i.e., interscapular area, thigh, flank), constituting archival diagnostic specimens collected between 2019-2020. Tumours were graded histologically according to the newly proposed soft-tissue sarcoma grading system in cats. Immunohistochemistry was performed to evaluate the expression of Ki67 and metallothionein in tumour cells. RESULTS: The cytoplasmic and sometimes nuclear expression of metallothionein was observed in all tumours grade I, 66.67% of tumours grade II and 55% of tumours grade III. The expression of metallothionein was negatively correlated with tumour grade and inflammation score, while the Ki67 index was positively correlated with tumour grade, inflammation score and necrosis score. CONCLUSION: The downregulation of MT expression in feline injection site fibrosarcomas seems to be connected with an increase in the inflammatory infiltration, hence tumour progression. This is the first study describing metallothionein expression in feline injection site fibrosarcomas.

Retrospective study of cutaneous neoplasms in horses treated at the Livestock Development Center of the Federal University of Bahia / Estudo retrospectivo das neoplasias cutâneas em equinos atendidos no Centro de Desenvolvimento da Pecuária da Universidade Federal da Bahia

The aim of this study was to determine the prevalence of cutaneous neoplasms in horses treated at the Center for the Development of Livestock at the Federal University of Bahia, as well as to correlate it with the coat color, breed, and age of the animal. For that, the attendance records for the last ten years were reviewed. When evaluating the files, 13 cases of cutaneous tumor in horses confirmed by histopathology and cytology were observed. The most prevalent skin tumors were sarcoid (38.5%), melanoma (23%), and fibrosarcoma (15.4%). Regarding the equine coat color, gray and sorrel horses were the most frequent with 30.7% and 23.1% of cases, respectively. As for the equine breed, the mangalarga marchador was the most prevalent (38.4%). Regarding age, 38.46% of the horses were up to 5 years old, 30.77% of the animals were between 4 and 10 years old, and 30.76% were between 11 and 16 years old. In the end, it can be concluded that sarcoid and melanoma were the most prevalent neoplasms.

Objetivou-se com este trabalho determinar a prevalência de neoplasias cutâneas em equinos atendidos no Centro de Desenvolvimento da Pecuária da Universidade Federal da Bahia, bem como correlaciona-la com a pelagem, raça e idade do animal. Para tanto revisou-se as fichas de atendimento dos últimos dez anos. Ao avaliar as fichas, observou-se 13 casos de tumor cutâneo em equinos confirmado por histopatologia ou citologia. Os tumores cutâneos mais prevalentes foram sarcoide (38,5%), melanoma (23%) e fibrossarcoma (15,4%). Com relação a pelagem, equinos tordilhos e alazões foram os mais frequentes com 30,7% e 23,1% dos casos, respectivamente. Quanto as raças, a mangalarga marchador foi a mais prevalente (38,4%). Em relação a idade, 38,46% dos equinos possuíam até 5 anos de idade, 30,77% dos animais apresentavam idade entre 4 e 10 anos e, 30,76% apresentavam idade entre 11 e 16 anos. Ao fim, pode-se concluir que o sarcoide e o melanoma foram as neoplasias mais prevalentes.

Sorafenib inhibits tumor cell growth and angiogenesis in canine transitional cell carcinoma.

Canine transitional cell carcinoma (cTCC) is the most common naturally occurring bladder cancer and accounts for 1-2% of canine tumors. The prognosis is poor due to the high rate of invasiveness and metastasis at diagnosis. Sorafenib is a multi-kinase inhibitor that targets rapidly accelerated fibrosarcoma (RAF), vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, platelet-derived growth factor receptor-ß (PDGFR-ß), and KIT. In previous studies, a somatic mutation of B-rapidly accelerated fibrosarcoma (BRAF) and expressions of VEGFR-2 and PDGFR-ß were observed in over 80% of patients with cTCC. Therefore, in this study, we investigated the anti-tumor effects of sorafenib on cTCC. Five cTCC cell lines were used in the in vitro experiments. All five cTCC cell lines expressed VEGFR-2 and PDGFR-ß and sorafenib showed growth inhibitory effect on cTCC cell lines. Cell cycle arrest at the G0/G1 phase and subsequent apoptosis were observed following sorafenib treatment. In the in vivo experiments, cTCC (Sora) cells were subcutaneously injected into nude mice. Mice were orally administered with sorafenib (30 mg/kg daily) for 14 days. Sorafenib inhibited tumor growth compared to vehicle control. The necrotic area in the tumor tissues was increased in the sorafenib-treated group. Sorafenib also inhibited angiogenesis in the tumor microenvironment. Thus, sorafenib may be potential therapeutic agent for cTCC via its direct anti-tumor effect and inhibition of angiogenesis.

Successful radiation treatment of undertail fibrosarcoma in a Major Mitchell's cockatoo (Lophochroa leadbeateri).

CASE DESCRIPTION: A male Major Mitchell's cockatoo (Lophochroa leadbeateri) of unknown age presented with an ulcerated mass on the ventral tail caudodorsal to the cloaca. CLINICAL FINDINGS: An impression smear of the mass showed spindle cell atypia. Multiple biopsies were submitted for histopathology with inconclusive results. A CT scan revealed a soft tissue mass causing compression of the cloacal lumen. The patient underwent surgical debulking, and a core of the mass was submitted again for histopathology, which reported it as fibrosarcoma. TREATMENT AND OUTCOME: Under repeated general isoflurane gas anesthesia, the patient received a course of definitive radiation therapy totaling 60 Gy and divided in 3 Gy X 20 fractions. By treatment completion, the lesion had decreased in size with necrotic debris on the surface. Surrounding tissues appeared healthy and no adverse effects were observed. As of 1.5 years post-treatment, the mass appears completely healed with no signs of reoccurrence. CLINICAL RELEVANCE: This case suggests that radiation therapy with this protocol could be an effective treatment option for fibrosarcoma in avian species.

Achados radiográficos e ultrassonográficos de fibrossarcoma em membro torácico de gatos: relato de três casos / Radiographic and ultrasound findings of fibrosarcoma in the cats: reports of three cases / Hallazgos radiográficos y ultrasonidos de fibrosarcoma en la extremidad torácica de gatos: informe de tres casos

O fibrossarcoma é uma neoplasia mesenquimal maligna originada dos fibroblastos que localiza-se especificamente em tecido cutâneo, subcutâneo e cavidade oral. A ressecção cirúrgica do tumor com margem de segurança é conhecida como a principal forma de tratamento. A principal forma de metástase é a via hematógena, atingindo pulmões, e menos comum em linfonodos regionais. A análise histopatológica é o exame diagnóstico de eleição para definição do tipo de tumor e sua graduação. Os exames de imagem são fundamentais no estadiamento das neoplasias e planejamento cirúrgico. A ultrassonografia e radiografia são os métodos mais utilizados e oferecem um grande apoio a oncologia médica veterinária. O exame radiográfico possibilita o achado de neoformações ósseas ou demais alterações como o aumento de volume de tecidos moles, infiltração gordurosa, e cavitações com gás ou fluído. O exame ultrassonográfico permite o conhecimento sobre a ecotextura, organização, e localização da lesão em tecidos moles. Em três gatos com fibrosssarcoma em membro torácico, foram realizadas radiografia e ultrassonografia específica da lesão. Os achados radiográficos foram aumento de volume, radiopacidade dos tecidos moles, sem acometimento ósseo. Os achados ultrassonográficos foram lesões de ecotextura grosseira, altamente heterogêneas. Os exames citológicos e histopatológicos revelaram tratar-se de fibrossarcoma. O presente relato tem como objetivo descrever os achados radiográficos e ultrassonográficos de fibrossarcoma em membro torácico de três gatos.

Fibrosarcoma is a malignant mesenchymal neoplasm originating from fibroblasts, which is specifically located in the skin tissue, subcutaneous tissue and oral cavity. Surgical resection of the tumor with a safety margin is known as the main form of treatment. The main form of metastasis is the hematogenous route, reaching the lungs, and less common in regional lymph nodes. histopathological analysis is the diagnostic test of choice for defining the type of tumor and its graduation. Imaging exams are essential in the staging of neoplasms and surgical planning. Ultrasonography and radiography are the most used methods and offer great support to veterinary medical oncology. The radiographic exam allows the finding of bone neoformations or other alterations such as the increase in soft tissue volume, fatty infiltration, and cavitations with gas or fluid. The ultrasound examination allows knowledge about the echotexture, organization, and location of the soft tissue lesion. Three cats with fibrosarcoma in the thoracic limb underwent lesion-specific radiography and ultrasound. The radiographic findings of fibrosarcomas were increased soft tissue radiopacity volume, without bone involvement. And the ultrasonographic findings were gross echotexture lesions, highly heterogeneous. Cytological and histopathological examinations were performed for definitive diagnosis. The present report aims to describe the radiographic and ultrasonographic findings of fibrosarcoma in the thoracic limb of three cats.

RESUMEN El fibrosarcoma es una neoplasia mesenquimatosa maligna que se origina a partir de fibroblastos, que se localiza específicamente en el tejido cutáneo, tejido subcutáneo y cavidad oral. La resección quirúrgica del tumor con un margen de seguridad se conoce como la forma principal de tratamiento. La principal forma de metástasis es la vía hematógena, que llega a los pulmones y es menos común en los ganglios linfáticos regionales. El análisis histopatológico es la prueba diagnóstica de elección para definir el tipo de tumor y su graduación. Los exámenes por imágenes son esenciales en la estadificación de las neoplasias y la planificación quirúrgica. La ecografía y la radiografía son los métodos más utilizados y ofrecen un gran apoyo a la oncología médica veterinaria. El examen radiográfico permite encontrar neoformaciones óseas u otras alteraciones como aumento de volumen de tejidos blandos, infiltración grasa y cavitaciones con gas o líquido. El examen ecográfico permite conocer la ecotextura, organización y ubicación de la lesión de tejidos blandos. A tres gatos con fibrosarcoma en la extremidad torácica se les realizó una radiografía y una ecografía específicas de la lesión. Los hallazgos radiográficos de los fibrosarcomas fueron un aumento del volumen de radiopacidad de los tejidos blandos, sin afectación ósea. Y los hallazgos ecográficos fueron lesiones macroscópicas de ecotextura, muy heterogéneas. Se realizaron exámenes citológicos e histopatológicos para el diagnóstico definitivo. El presente informe tiene como objetivo describir los hallazgos radiográficos y ecográficos del fibrosarcoma en la extremidad torácica de tres gatos.

Invasive Tendon Sheath Fibrosarcoma Causing Radial Osteolysis in a Golden Retriever.

This case report details a previously undescribed malignancy of the tendon sheath in a golden retriever. This dog originally presented with lameness of the left forelimb, at which point radiographs revealed a monostotic, lytic lesion of the distal radius with overlying soft-tissue swelling. A fine-needle aspirate was performed, and cytology was compatible with a sarcoma, with the primary differential being an osteosarcoma. After amputation, the leg was submitted for histopathology, which revealed inconsistencies with a typical osteosarcoma lesion, including lack of osteoid deposition. Second opinion histopathology showed a fibrosarcoma that appeared to have originated in the tendon sheath of an extensor tendon and then secondarily invaded the radius. At the time of publication, ∼17 mo after amputation, the dog continues to do well without any evidence of recurrent or metastatic disease.

Intramuscular Grade 1 fibrosarcoma: Magnetic resonance imaging findings in 2 dogs.

Two adult neutered male dogs were presented for evaluation of firm, painless masses arising within muscle: an 8-year-old German wirehaired pointer dog with an accessory tricipital growth, and a 3-year-old German shepherd dog with a gracilis muscle growth. Magnetic resonance imaging (MRI) characteristics suggested malignant behavior, with a central fluid-like portion with a hyperenhancing lining, a nidus of disorganized tissue, and an extensive reactive zone, whereas histopathology was consistent with low-grade fibrosarcoma. This report describes histologically low-grade, yet biologically high-grade intramuscular fibrosarcoma, in which MRI provided detailed information on tumor behavior and assisted with biopsy and surgical planning.

Fibrosarcome intramusculaire de Grade 1 chez deux chiens : Imagerie par résonance magnétique. Ce rapport de cas décrit des fibrosarcomes intramusculaires de bas grade histologique mais au comportement biologique de haut grade ainsi que leur imagerie par résonance magnétique (IRM) chez deux chiens mâles castrés évalués pour des masses musculaires fermes et indolores : un Braque Allemand de 8 ans avec une masse originant de la branche accessoire du muscle triceps, et un Berger Allemand de 3 ans avec une masse au muscle gracile. L'IRM a révélé une zone centrale liquide bordée d'une mince couche au rehaussement marqué, adjacent à un foyer de tissu désorganisé, entourés par une zone réactive étendue. L'histopathologie des lésions révèle un fibrosarcome et malgré la présence d'anomalies histologiques de bas grade, l'infiltration des muscles adjacents est documentée par microscopie et les caractéristiques d'imagerie sont celles associées chez l'humain avec un comportement malin.(Traduit par les auteurs).

Gigantic Ocular Squamous Cell Carcinoma Mixed With Fibrosarcoma in a Mare: Clinical, Laboratory, Ultrasonography and Histopathology Findings.

Ocular neoplasms represent 10% of all equine neoplasms and ocular squamous cell carcinoma (OSCC) is the most common one. This report describes the clinical presentation, laboratory, ultrasonography, postmortem, histopathology and immunohistochemistry findings of a mixed ocular neoplasm in a 10-year-old draft mare. The mare had a one-year history of left ocular mass. Complete destruction of the left eye with loss of vision was observed. A large ulcerated mass oozing blood replaced the left eye. Left parotid lymph node was swollen and had a sinus tract discharging pus. Ultrasonography revealed absence of all intraocular structures, several lobular echogenic tissues and several hyperechoic areas of ossification with acoustic shadowing. Color Doppler scanning revealed numerous neovascularization all over the tumor, particularly along the periphery. The neovascularization demonstrated mainly arterial with few mixed blood flow signals. The amplitude of systolic and diastolic blood flow was markedly increased. Enucleation was decided but the mare died just after examination. The ocular mass was excised and its weight was 390 g. Postmortem examination revealed no distant metastasis in all internal organs. Histopathology confirmed OSCC mixed with fibrosarcoma and associated with cartilaginous and osseous metaplasia. The neoplastic cells gave positive nuclear p53 immunoreactivity. The left parotid lymph node revealed metastasis. Despite the unsuccessful outcome in this particular case, this report documents a mixed eye neoplasm, highlights the ultrasonography and histopathology features of OSCC, and reinforces the need for early diagnosis and surgical treatment in such cases to improve the outcome and to decrease the drastic complications and mortality.

Endosialin (CD248) Expression in Fibromas and Soft-tissue Fibrosarcomas in Dogs.

BACKGROUND/AIM: Endosialin is present in human fibrosarcoma neoplastic cells. This study aimed to analyse the expression of selected cellular proteins found in fibrosarcomas and soft-tissue fibroids in dogs. MATERIALS AND METHODS: A total of 71 skin tumours obtained from dogs were used. The samples included 31 fibromas and 40 fibrosarcomas. Histopathological evaluation was performed according to World Health Organization guidelines. Immunohistochemistry was performed with anti-endosialin, Ki-67, cyclo-oxygenase 2 and vimentin antibodies and assessed using the semi-quantitative scale. RESULTS: Endosialin expression was observed in 82.5% of fibrosarcomas and in 35% of fibromas. A significant positive correlation was found between the expression of endosialin in fibrosarcoma neoplastic cells and the degree of histological malignancy and the expression of the Ki-67 and cyclo-oxygenase 2 antigen. Expression of vimentin confirmed mesenchymal origin of this tumours. CONCLUSION: The results of our research suggest that endosialin is involved in the carcinogenesis of fibrosarcoma in dogs.

Expression of PDGF-A, PDGFRA, integrin subunit alpha V and selectin E is increased in canine cutaneous fibrosarcomas.

We investigated the expression of platelet derived growth factor alpha (PDGFA); its receptor, PDGFRA; integrin subunit alpha V; and selectin E in cutaneous fibrosarcomas in dogs. Ten cases of canine fibrosarcomas were obtained from the archive of the Department of Pathology, Ondokuz Mayis University, Samsun. Tissue sections were cut and stained with hematoxylin and eosin, Alcian blue-periodic acid Schiff, Masson's trichrome, and also immunostained. Eight tumors classified as spontaneous fibrosarcomas exhibited interwoven bundles of spindle shaped cells with oval to plump nuclei and scant cytoplasm, while two tumors exhibited features of injection site fibrosarcoma with peripheral infiltration of mononuclear cells and intratumor necrosis. We found that neoplastic cells from all cases exhibited cytoplasmic expression of PDGFA, and cytoplasmic and nuclear staining for PDGFRA. Integrin subunit alpha V immunostaining was observed in all cases, while selectin E expression was observed in vascular endothelial cells and neoplastic cells. A significant positive correlation was found between the expression of PDGFA and integrin subunit alpha V. Our findings indicate that PDGFA, PDGFRA, integrin subunit alpha V and selectin E are expressed strongly in canine cutaneous fibrosarcomas and may contribute to tumor progression.

Canine Primary Corneal Fibrosarcoma - Case Report.

This is the first report of a primary corneal fibrosarcoma in a canine. A 4-year-old male dog, Blue Heeler, owas examined because of a reddish nodular mass in the right eye. A complete ophthalmic exam was conducted, including slit-lamp biomicroscopy, applanation tonometry, fundoscopy, ocular and abdominal ultrasound, hemogram, serum biochemistry profile, and a thoracic X-ray. After the ophthalmic evaluation of the right eye, conjunctival hyperemia and the presence of a .5 cm diameter mass was found in the cornea. The diagnosis of fibrosarcoma was confirmed by histopathological analysis. The keratectomy showed satisfactory results in the removal of the corneal fibrosarcoma. The patient was followed up on for 18 months after the surgical procedure, and there were not any signs of local recurrence or metastasis.

Diagnostic Yield of Micro-Computed Tomography (micro-CT) Versus Histopathology of a Canine Oral Fibrosarcoma.

Micro-computed tomography (micro-CT) imaging currently gains increased interest in human as well as veterinary medicine. The ability to image 3-dimensional (3D) biopsy specimens nondestructively down to 1 µm spatial resolution makes it a promising tool for microscopic tissue evaluation in addition to histopathology. Visualizing tumor margins and calculating tumor load on 3D reconstructions may also enhance oncological therapies. The objective of this study was to describe the workflow from tumor resection to histopathological diagnosis, using both routine hematoxylin-eosin (HE)-stained sections and micro-CT tomograms on a stage II oral fibrosarcoma in a 7-year-old Hovawart dog. The maxillectomy specimen was fixed with formalin and stained with an X-ray dense soft tissue contrast agent. Micro-CT imaging was done using an ex vivo specimen micro-CT device. Tumor margins could not be exactly determined on micro-CT tomograms due to limited image resolution and contrast. Histopathology was performed after washing out the contrast agent. It showed neoplastic cells infiltrating the surrounding tissue further than assumed from micro-CT images. A total tumor volume of 10.3 cm3 could be calculated based on correlating micro-CT tomograms with HE-stained sections. This correlative approach may be of particular interest for oncological therapy. More than that, micro-CT imaging technology supported histopathology by means of 3D orientation and selection of slices to be cut on determining tumor margins. In this clinical case report, micro-CT imaging did not provide unambiguous clinical evidence for oncological decision-making, but it showed potential to support histopathology and calculate tumor volume for further clinical use.

Fibrosarcoma with sarcomatosis and metastasis in a FeLV-negative cat.

A 6-year-old, spayed female, mixed shorthair cat presented to the emergency service at The Ohio State University Veterinary Medical Center for evaluation of hypercalcemia, a right eye mass, and multiple intrathoracic and intra-abdominal masses. Cytologic evaluation of one of the abdominal masses revealed a uniform population of large, anaplastic mesenchymal cells found individually, in loose aggregates, and occasionally associated with pink, extracellular matrix. The cytology was consistent with a malignant mesenchymal neoplasm, with primary consideration given to fibrosarcoma and hemangiosarcoma. The cat was euthanized and histopathology confirmed disseminated fibrosarcoma. Fibrosarcoma comprises 12%-41% of feline cutaneous tumors and affects cats at a mean age of 9.6 years. Three manifestations of fibrosarcoma predominate in cats: spontaneous solitary fibrosarcoma, vaccine-induced/injection site fibrosarcoma, and oncogene-induced (FSV) fibrosarcoma. The history, signalment, and results from diagnostics performed did not support solitary fibrosarcoma or injection-induced sarcoma. Although some criteria fit with virally induced fibrosarcoma, such as age and the presence of multiple fibrosarcomas, the neoplastic population was negative for FeLV IHC. The presence of fibrosarcomas throughout the pleural and peritoneal cavity was most compatible with sarcomatosis and the distant metastasis of an unidentified primary neoplasm. To the authors' knowledge, this is the first reported case of sarcomatosis in a FeLV-negative cat.

Primary intracranial fibrosarcoma in a southern sea otter Enhydra lutris nereis.

Southern sea otters Enhydra lutris nereis, a threatened marine mammal species, face numerous environmental and infectious disease challenges in their native habitat of coastal California, USA. However, there are few published cases describing neoplasia in sea otters despite their relatively long life span when cared for in aquarium settings. An 18 yr old neutered male southern sea otter, born and raised in human care, presented with an acute onset of seizures and dull mentation. Magnetic resonance imaging of the head revealed a large, central brain lesion. After no improvement with treatment, euthanasia was elected due to a poor prognosis. Grossly, a poorly demarcated, granular, tan mass expanded the cranial meninges in the longitudinal fissure at the level of the cruciate sulcus and extended into the underlying gray matter and superficial white matter. Histologically, the mass was composed of spindle cells, forming haphazardly arranged interlacing bundles and herringbone patterns, with a high mitotic count, moderate cellular pleomorphism, and prominent vascularization. Neoplastic cells demonstrated positive immunoreactivity for vimentin and negative immunoreactivity for smooth muscle actin, factor VIII-related antigen, S100, melan-A, E-cadherin, desmin, glial fibrillary acidic protein, and cytokeratin AE1/AE3. Based on gross, histologic, and immunohistochemical findings, the mass was most consistent with a primary intracranial fibrosarcoma (PIF). PIFs are a rare neoplasm in both humans and other animals with few reports in the veterinary literature. This is the first recorded case of a PIF in a sea otter.

Treatment of feline injection-site sarcoma with surgery and iridium-192 brachytherapy: retrospective evaluation of 22 cats.

OBJECTIVES: The aim of this retrospective descriptive study was to determine the effectiveness of using iridium implants in addition to surgery in cats with feline injection-site sarcomas (FISSs) in terms of time to progression and disease-specific survival and to identify prognostic factors for patient outcome. METHODS: Medical records of cats presented at our institution with FISS were reviewed. Inclusion criteria included histologic diagnosis of a tumor type associated with post-injection neoplastic development, tumor located at a site associated with vaccination, no other therapies prior to the administration of brachytherapy with the exception of surgery and adequate follow-up data. RESULTS: Twenty-two cats with FISS were treated with surgery and brachytherapy delivered by postoperative iridium-192 interstitial implants. Radiation doses ranged from 4000 to 6000 cGy (median dose 5079.55 cGy), with most doses delivered over 7 days. The median number of surgeries prior to brachytherapy was one (range 1-4). The complications associated with postoperative brachytherapy were typically mild, although four cats developed more severe complications. The median time to progression for all cats was 619 days and disease-specific survival time for all cats was 1242 days. The 1 and 2 year tumor-free rates in these cats were 63.6% and 40.9%, respectively. The local failure rate was 54.5% and the distant failure rate was 13.6% due to lung metastasis. There was a significant difference in time to progression of cats that had a single surgery performed prior to brachytherapy and those that had multiple surgeries (undefined vs 310 days; P = 0.01). There were no other statistically significant identified prognostic factors. CONCLUSIONS AND RELEVANCE: These data suggest that the addition of brachytherapy postoperatively in cats with FISS was well tolerated and is comparable to other forms of adjuvant therapy.

Epidemiological and Pathological Characterization of Feline Injection Site Sarcomas in Southern Brazil.

Feline injection site sarcoma (FISS) is a mesenchymal neoplasm with highly malignant characteristics. These tumours originate in anatomical sites where there has been previous parenteral administration of medicinal substances or implantation of medical devices. The aim of this study was to investigate the epidemiological and pathological features associated with FISS in the southern region of Brazil. The database of the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul was searched for excisional and incisional biopsy samples compatible with FISS submitted between 2007 and 2017. Biopsy reports were reviewed and epidemiological information, including breed, age and sex of affected cats, as well as gross findings including anatomical location and size of the tumour and the presence of tissue invasion, were extracted. Eighty-nine samples were selected based on the established criteria. Most animals were of undefined breed and were female cats with a median age of 10 years. Grossly, 84.8% of the tumours were >2 cm in diameter. Regarding anatomical location, 34.9% of the tumours were located in the subcutaneous tissue of the thoracic wall, 29.2% in the flank, 21.3% in the interscapular region and 14.6% in the limbs. Histologically, the tumours originated in the subcutaneous tissue and were diagnosed as malignant mesenchymal neoplasms. Most were compatible with fibrosarcomas, but variants with features of pleomorphic sarcoma or chondrosarcoma were recognized. All tumours exhibited areas of necrosis and peripheral inflammatory infiltrate, composed predominantly of lymphocytes, plasma cells and macrophages. The results of this study suggest the need for dissemination of information on FISS epidemiology and guidelines for management of this tumour to veterinarians in the region.