5 research outputs found

    Extramedullary plasmacytoma in a captive collared peccary (Pecari tajacu)

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    Abstract: An extramedullary plasmacytoma case in a captive collared peccary (Pecari tajacu) is reported. The animal, a female aging three years old, had a medical history of diffusely distributed skin and mucocutaneous junction lesions, associated with swollen lymph nodes. Clinical examination and complementary exams (complete blood count, biochemical analysis, skin scraping to search mites and fungal culture) were performed. Thirty days after examination, the animal died. At necropsy, multiple consistent nodules, aseptic pustules and swollen lymph nodes were found. On histological exams of the skin and oral mucosa, we observed a large number of round cells forming masses organized in nests, sheets, and cords of cells in a well-vascularized fibrovascular tissue. Neoplastic plasma cells infiltrated between the fibers and the lamina propria of smooth muscle. Spaces among the cell masses were filled with some eosinophil and fluid. Most of the cells were well differentiated, presenting a perinuclear clear zone. In some points, the cells were pleomorphic. The plasma cells presented eccentric, basophilic and spherical nuclei, showing a dense to organized chromatin with distinct nucleoli. Binucleate cells were observed, but multinucleated giant cells were rare. Oral mucosa and lymph nodes tested by immunohistochemical analyses were positive for Mb-1, with a multifocal distribution. In regard to Bcl-2, the neoplastic cells were intermittent weakly positive. So, an extramedullary plasmacytoma was diagnosed in the collared peccary considering the location, the histopathological and immunohistochemical findings

    Canine balloon and signet-ring cell melanomas: a histological and immunohistochemical characterization.

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    Item does not contain fulltextSeven tumours that were composed of balloon (n=4) or signet-ring (n=3) cells were investigated for a putative melanocytic origin. The tumours were located in the skin or the mouth cavity. In one case a sample from inguinal lymph node metastasis was available. Two antibodies used in man for the immunohistochemical diagnosis of melanomas, namely anti-Melan-A and anti-tyrosinase, were examined for their cross-reactivity with the corresponding canine antigens. The Melan-A antibody labelled all balloon cell tumours and one signet-ring cell tumour, whereas the anti-tyrosinase antibody was not reactive in any of the tumours. The Melan-A antibody also labelled a variety of canine epithelioid and spindle cell melanomas; non-melanocytic tumours were all negative. This study confirmed the occurrence of balloon and signet-ring cell melanomas in dogs. Melan-A antibody was found to be useful in the diagnosis of pigmented and non-pigmented canine melanomas

    Melanoma amelanótico em cães: estudo retrospectivo de 35 casos (2004-2010) e caracterização imuno-histoquímica

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    Melanomas são tumores agressivos de melanócitos que ocorrem principalmente na cavidade oral, nas junções mucocutâneas e na pele de cães. Este tipo de neoplasma pode apresentar diversos graus de pigmentação melânica, incluindo total ausência (melanomas amelanóticos [MA]). Os arquivos de biópsia do SPV-UFRGS, que compreendem o período de 2004 a 2010, foram revisados e levantados os casos de neoplasias melanocíticas em cães. Realizou-se estudo retrospectivo de 35 casos de MA e caracterização pela imuno-histoquímica (IHQ). As principais raças acometidas foram o Poodle, Dachshund e Cocker Spaniel, mas o maior número de casos foi observado em cães sem raça definida (SRD). A idade média desses cães foi de 10,7 anos (variação de 5 a 18 anos) e não houve predileção por sexo. As principais localizações incluíram cavidade oral (57,1%) e dígitos (17,1%). Histologicamente, 40% dos MA foram classificados como epitelioides, 34,3% como mistos e 25,7% como fusiformes. Na avaliação IHQ, 86,6% dos casos foram positivos para a vimentina, 70% para a proteína S-100 e 56,6% para o melan-A. Os resultados obtidos neste trabalho possibilitam concluir que os cães com MA caracterizavam-se por serem velhos. A forma celular mais observada foi a epitelioide. Devido a pouca diferenciação desses tumores, ressalta-se a importância da realização do painel imuno-histoquímico, sobretudo da proteína S-100, que apresentou melhor marcação que o melan-A
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