Parasitic myelopathy caused by Gurltia paralysans in domestic cats is a disease commonly reported in several South American countries. The adult parasite is lodged in the meningeal veins and spinal cord, often causing clinical manifestations of vascular proliferation, thrombophlebitis, and medullary compression. Wild felines are believed to be the definitive hosts of this parasite. The infection occurs through the ingestion of paratenic hosts, but the life cycle of G. paralysans is not yet clearly understood. In this paper, we discuss a case of parasitic myelopathy in a margay (Leopardus wiedii) that died during post-surgical care. Necropsy revealed focal hemorrhages in the thoracolumbar spinal cord. A microscopic examination revealed adult nematodes and eggs inside the veins of subarachnoid space in spinal cord, suggesting G. paralysans infection. This is first description of parasitic myelopathy in a margay in Brazil.

This study aimed to characterize the prevalence and clinical, macroscopic and histopathological aspects of dogs affected by testicular tumors based on biopsy specimens from the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria (LPV-UFSM) over 19 years. Parameters regarding the age, size, and breed of the affected dogs were also established. Of all dogs with some type of neoplasm submitted to histopathological analysis at the LPV over these 19 years (n=1,900), 213 (11.2%) had at least one testicular neoplasm. The tissues of 190 dogs (with 220 neoplasms) were available for histological reassessment. The dogs in this study had different types of testicular tumors with relatively similar frequencies. In descending order, the most frequent testicular neoplasms were seminomas (88/220), Leydig (interstitial) cell tumor (LCT; 64/220), Sertoli cell tumor (SCT; 61/220), and mixed germ cell-sex cord stromal tumor (MGSCT) (07/220). Among the dogs of defined breed (119 cases), large breeds had the largest number of cases (50/119), followed by small (47/119) and medium-sized (22/119) breeds. The ages of dogs affected by testicular tumors ranged from 10 months to 18 years. Increased testicular volume was the most common clinical manifestation. Eleven dogs presented information about clinical signs suggestive of hyperestrogenism syndrome (feminization). In seminomas, the diffuse pattern predominated over the intratubular pattern. Two sites (luminal and basal compartments) suggestive of the onset of neoplastic transformations in germ cells were observed in intratubular seminomas. They corroborate the hypothesis that canine seminomas possibly have pathogenesis similar to that observed in human spermatocytic seminomas. The SCTs and LCTs presented high cell morphology variation. SCTs had neoplastic cells organized in five different histological arrangements. As for LCT, solid-diffuse and cystic-vascular histological patterns were the most commonly observed. Through this study, it was possible to establish some of the leading clinical, macroscopic, and histopathological aspects of testicular neoplasms diagnosed over 19 years in the area covered by the LPV-UFSM.

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RESUMO A criocirurgia tem sido utilizada no tratamento de diferentes enfermidades de sistemas e órgãos. Contudo, são relatados efeitos adversos, como cicatrização lenta, cicatrizes extensas, disfunção estética e funcional. As lesões que ocorrem naturalmente pela exposição ao frio extremo, comumente, resultam em gangrena. O presente trabalho teve como objetivo avaliar a influência das células-tronco mesenquimais de origem adiposa (ADSCs) na fase de proliferação da cicatrização de feridas cutâneas. Por meio da aplicação do nitrogênio líquido pela técnica do spray aberto, realizou-se a indução de uma ferida, de aproximadamente 15mm de diâmetro, na região dorsal de cada rato. A ferida recebeu o tratamento de acordo com o grupo ao qual pertencia: 1) aplicação das ADSCs no 15º dia (grupo tratado); 2) aplicação da solução cloreto de sódio 0,9% no 15º dia (grupo sham); 3) nenhuma intervenção até o momento da eutanásia (grupo controle). O grupo tratado com as ADSCs apresentou as maiores taxas de contração média das feridas e obteve diferença estatisticamente significativa em relação ao grupo sham quanto à neovascularização. A terapia com as ADSCs proporcionou uma relevante evolução clínica das feridas, podendo ser constatada ao final do período de avaliação por cicatrizes mais estreitas e compridas.

Due to the high prevalence of mast cell tumors (MCTs) in the diagnostic routine, several factors, especially prognostic, have been sought to determine the biological behavior of these neoplasms. Immunohistochemistry (IHC) is one of the main tools utilized to biologically differentiate more aggressive tumors from less aggressive ones. However, some immunostainings are influenced by formalin fixation, interfering with the results. This is both a retrospective and prospective study of MCTs diagnosed in laboratory routine. A total of 25 samples, without knowledge about fixation time, were analyzed in the retrospective study, whereas 12 samples, with known fixation times, were assessed in the prospective study. Two histologic grading systems (Patnaik and Kiupel), special staining of toluidine blue, and IHC for KIT and Ki67 proteins were applied in both studies. Additionally, two amplification systems (biotinylated and non-biotinylated) for Ki67 protein and counting of the argyrophilic nucleolar organizing regions (AgNOR method) were tested in the prospective study. In the retrospective study, greater agreement between the evaluating pathologists was observed when the Kiupel system was used. IHC staining for KIT protein was effective in both studies, regardless of fixation time. IHC staining for Ki67 protein was highly sensitive to formaldehyde, and staining failure was observed in 56% of the cases in the retrospective study. In the prospective study, samples fixed for longer than 24 hours showed a reduction in the number of stained cells (altering the determination of the cell growth fraction) or showed absence of IHC staining in both amplification systems. The use of the AgNOR method to evaluate the rate of cell proliferation may be an alternative when the fixation time of the neoplasm is unknown or longer than 24 hours.

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Background: Osteosarcoma is a malignant mesenchymal tumor with a wide variety of histological patterns. It is the primary bone neoplasia diagnosed in most domestic animal clinic, but rare in farm animals. The tumor develops both the appendicular skeleton as the axial skeleton, the latter being less affected. Generally it has a fast, painful and infiltrative grow, being observed metastasis. This study aims to report a case of metastatic osteoblastic osteosarcoma in the nasal bone of a bovine, diagnosed at the Animal Pathology Laboratory at the University of Passo Fundo (UPF), featuring its pathological and immunohistochemical aspects.Case: A 5 year old Wagyu female beef cattle, was treated at the Veterinary Hospital of the University of Passo Fundo. The animal had swelling in the left nasal plan, dyspnoea and anorexia. It was held cytology and biopsy which revealed malignant mesenchymal neoplasm compatible with osteosarcoma. The clinical picture has worsened and the animal died. At necropsy, the left nasal plane, had ulcerated tumor mass measuring 15x12.5x7.5 cm, hard and firm consistency with whitish color that seeped up to the turbinates and sinuses. In the lung, there were numerous nodules of tumor appearance, adhered to the parietal pleura, similar to bone tissue. In the histopathological analysis, proliferation of neoplastic cells located in the deep dermis was observed, cell thick, well-defined and infiltrative, arranged in bundles, loosely grouped with rounded shape, sometimes oval, with distinct boundaries. There were areas with formation of osteoid matrix calcification and tumor necrosis. It was observed lung and regional lymph nodes metastasis. Tissue samples were subjected to immunohistochemistry (IHC), was performed using the polymer method with horseradish peroxidase (HRP), with positive control, using a panel of antibodies. Neoplastic cells were immunoreactive for vimentin and negative for other antibodies. Thus, confirmed the case of mesenchymal origin and bone tumor.Discussion: Osteosarcoma developing in the axial skeleton, more precisely in the nasal bone, in animals of this age group, is not found frequently in the literature. However, when they occur, they have unilateral injury, remarkable facial deformities, dyspnea and infiltration of adjacent tissues. During necropsy there was observed a mass of hard consistency suggesting bone tissue in the nasal plane, there was also observed whitish spots on the lung and lymph nodes. Through microscopic analysis was obtained the classification of osteoblastic osteosarcoma. Being a malignant tumor it has a fast and infiltrative growth, there was visualized metastasis in lung and mediastinal lymph nodes. The samples submitted to immunohistochemistry were positive for vimentin and negative for other antibodies. No treatment with chemotherapy, radiation therapy or surgical intervention to remove the tumor was possible to be performed. Due to the severity of the clinical condition, the mass location, which couldn’t be obtained a safe surgical margin and it was financially unviable. The presumptive diagnosis of osteosarcoma was based on clinical history, anamnesis and cytological examination. However, the histopathological examination was essential to confirm the diagnosis. Through immunohistochemical examination, it was found the histogenesis, allowing to exclude other neoplasias. This technic was essential to characterize osteosarcoma due to the shortage reports of this neoplasia in farm animals, therefore, very important in veterinary medicine diagnosis.Keywords: neoplasia, bone, axial skeleton, ruminant, immunohistochemical and anatomopathological aspects.

Background: Gastric neoplasms are uncommon in dogs, especially those affecting smooth muscle layers. Leiomyoma is a smooth muscle benign neoplasm, which requires surgical resection. Pylorectomy and gastroduodenostomy (Billroth I procedure) is the most indicated technique in cases not affecting the biliary and pancreatic tracts. Thus, the purpose of this study was to report a successful case of Billroth I procedure in a bitch presenting antrum pyloric obstructive leiomyoma. Case: A 12-year-old, non-spayed, Cocker Spaniel bitch was admitted presenting depression, hyporexia, postprandial vomiting and sparse episodes of hematemesis, for 30 days. Clinical suspicion on obstructive gastric outflow disease was established. Bloodwork (complete blood count, BUN, albumin, ALP and ALT), abdominal ultrasound and thoracic radiographs were assessed. The patient undergone upper gastrointestinal endoscopy. On endoscopic evaluation, small hemorrhagic mucosa ulcers were visualized on the gastric body, antrum and pylorus. Moreover, a sessile, ulcerated, round-shape and infiltrated antral-pyloric mass was seen. The mass was 1.5-2.0 cm in diameter and apparently involved the smooth muscle layer, causing severe pyloric obstruction. However, endoscopic evaluation of the duodenum was possible. Several biopsy samples were taken from the neoplasm and sent for histopathologic assessment. The result was not conclusive due to low quality samples. The patient had progressive worsening of obstruction episodes and required surgery. A wide-margin pylorectomy and gastroduodenostomy (Billroth I procedure) was carried out. The retrieved specimen was sent to histopathological and immunohistochemistry (IHC) assessment. Positive staining for actin and desmin confirmed smooth muscle origin of the mass and histopathological assessment confirmed leiomyoma. The patient underwent regular periodic postoperative assessments, revealing progressive clinical improvement and normal weight gain. Control upper gastrointestinal endoscopy was performed. Gastric ulcers were completely healed and gastroduodenal anastomosis was functional. The anastomotic scar tissue was sampled and revealed chronic and normal healing process. Complete healing was confirmed and the patient was discharged. Discussion: Gastric neoplasms are not common in dogs. However, severe obstruction of gastric outflow is a potential risk for complications in those cases. Upper gastrointestinal endoscopic assessment is important not only for diagnosis, but also for surgery decision making. In the current study, gastroscopy provided accurate preoperative evaluation of severity of pyloric obstruction and diagnosis of secondary gastric ulcers. Direct visualization of lesions and multiple biopsy sampling were performed. The presence of neoplasms over 2-cm in diameter indicates need for complete laparoscopic or conventional surgical resection. In this case report, open resection was carried out due to prohibitive cost of laparoscopic approach, mass dimensions and probable involvement of deeper tissue layers. In conclusion, pylorectomy and gastroduodenostomy (Billroth I procedure) was curative and provided good prognosis following resection of an antrum pyloric obstructive leiomyoma. Endoscopy was critical for both diagnosis and decision-making towards surgery for gastric outflow obstruction due to an antrum pyloric neoplasm. Histopathological and immunohistochemistry assessment confirmed neoplasm type and assured oncological safety of resection with wide margins. Keywords: gastric neoplasms, smooth muscle tumor, endoscopy, dog.