RESUMO
The clinical, radiological and pathologic features of a biphasic synovial sarcoma in the left elbow joint of a two-year-old male Rottweiler are presented. The tumor showed positive immunoreactivity for vimentin, Epithelial Membrane Antigen (EMA), p53 and PCNA, while it was negative for the cytokeratin used, S-100, Rb and p21. Immunohistochemistry for EMA allowed the identification of epithelioid components of synovial sarcoma, and may, therefore, contribute in establishing a diagnosis of biphasic synovial sarcoma. Intratumoral variation in PCNA immunoreactivity was minimal, indicating that the various tumor components proliferate at more or less similar rates. Overall, the characterized immunohistochemical profile for canine synovial sarcoma, not defined previously, may provide clues to the histogenesis of the phenotypically mesenchymal and epithelial elements of the tumor, and may be of value in the differential diagnosis of challenging cases, decreasing the risk of under- and mis-diagnosis. Although more cases need to be studied to determine whether there is a consistent pattern of immunostaining in canine synovial sarcoma, its potential significance is discussed in relation to the histogenesis, molecular pathology and differential diagnosis of canine synovial sarcoma.
Assuntos
Animais , Cães , Masculino , Mucina-1/análise , Doenças do Cão/patologia , Articulação do Cotovelo/anormalidades , Membro Anterior , Histocitoquímica/veterinária , Imuno-Histoquímica/veterinária , Queratinas/análise , Proteína Oncogênica p21(ras)/análise , Antígeno Nuclear de Célula em Proliferação/análise , Proteína do Retinoblastoma/análise , Sarcoma Sinovial/química , Neoplasias de Tecidos Moles/química , Proteína Supressora de Tumor p53/análise , Vimentina/análiseRESUMO
Synovial sarcoma is a malignant soft tissue neoplasm that occurs frequently in the extremities of young adults, near large joints. The lung is a common site of metastasis but an extremely unusual primary site for synovial sarcoma. We report an unusual case of primary synovial sarcoma that arose in the lung of a 59-year-old woman. The tumor had histologic and immunophenotypic features consistent with biphasic synovial sarcoma. These features included of an intimate admixture of cytokeratin and epithelial membrane antigen(EMA)-positive neoplastic epithelial cells and vimentin-positive fibroblast-like spindle cells. The patient had a closed thoracomy drainage and doxycycline pleurodesis for malignant loculated effusion and showed tumor extension in the left whole lung 4 months after pleurodesis. This case is an usual addition to the small number of published reports on primary pulmonary synovial sarcoma. The distinctive features of this neoplasm allow it to be distinguished from a variety of primary and metastatic malignancies in the lung.