Paratesticular pleomorphic rhabdomyosarcoma in the elderly - An immunohistochemical, ultrastructural study and review of the literature

A case of paratesticular pleomorphic rhabdomyosarcoma, presenting as an ulc erated mass in the left hemiscrotum of an 83-year-old man, is reported. By light microscopy, this neoplasm could not be distinguished from other pleom orphic sarcomas, such as malignant fibrous histiocytoma, leiomyosarcoma, an d liposarcoma. Immunohistochemistry showed that most tumor cells were stron gly reactive with antibodies directed against myoglobin, desmin, alpha-sarc omeric actin, and myogenin, whereas alpha-smooth muscle actin expression wa s less extensive. Electron microscopic examination demonstrated thick and t hin filaments with condensations of electron-dense material reminiscent of structures of Z-lines in the large pleomorphic cells. On the basis of these findings, the neoplasm was classified as a pleomorphic rhabdomyosarcoma. A ccording to a review of the literature, this is the first well-documented e xample of paratesticular pleomorphic rhabdomyosarcoma in an elderly person.