Leiomyosarcoma of the skin and subcutaneous tissue in a nellore cow
Pires, Ana Paula de CastroBarbosa, José DiomedesCosta, Samay Zillmann RochaOliveira, Mariana CorreiaOliveira, Carlos Magno ChavesBrito, Marilene de Farias
Background: Leyomiosarcomas are uncommon malignant smooth muscle tumors of hollow organs. Bovine leyomiosarcomas have been described in several sites, but smooth muscle tumors that arise from the skin are rare in domestic animals. These neoplasms may show variable histologic features depending on their grade of differentiation; therefore, diagnostic tools as special stain, electron microscopy and immunohistochemistry are essential for the definitive diagnosis. Due to the lack of reports of skin leyomiosarcomas in cattle, we described the occurrence of a leyomiosarcoma in the skin and subcutaneous tissue of a Nellore cow. Case: A 10-year-old Zebu Nellore cow was admitted at the Veterinary Diagnosis Center (CEDIVET) of Pará Federal University (UFPA), Brazil, to investigate a tumor on the hip. At clinical examination the cow showed a decreased appetite and weight loss. Due to the bad prognosis the veterinarian recommended euthanasia. Representative tissue samples were submitted for histopathological and immunohistochemistry evaluation at the Department of Pathology of the Federal Rural University of Rio de Janeiro (UFRRJ). The slides were stained by Hematoxylin and Eosin (HE), Massons trichrome and Van Gieson stains and submitted for immunohistochemistry with primary antibodies vimentin, troponin C, smooth muscle alpha actin and desmin. Grossly, the tumor appeared as a multilobular, ulcerated and firm 30 cm diameter mass with black and hemorrhagic areas on the surface. The mass was scattered throughout the subcutaneous tissue and infiltrated the adjacent muscle. On light microscopy, the neoplasm consisted of a non-encapsulated proliferation into the derma, composed of highly pleomorphic spindle to round cells arranged in broad interlacing fascicles and small islands. Metastatic lesions were found in the lungs and local lymph nodes. Massons trichrome stain revealed collagen production and Van Gieson stains was inconsistent...(AU)
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