Rabdomiossarcoma vesical em paciente idoso. Estudo imuno-histoquimico / Rhabdomyosarcoma of bladder in an elderly man. Immunohistochemical study

ABSTRACT

Malignant urinary bladder tumors of mesenchymal origin are extremely uncommon in man. The incidence of these tumors ranges from 0,23 percent to 0,67 percent of all bladder neoplasms. The authors herein report a rare case of rhabdomyosarcoma of the urinary bladder, a type of striated muscle tumor, in an 84-year-old man. The patient presented with a 3-month history of urinary symptoms. Ultrasonography and cystoscopic examination were performed. The patient underwent partial cystectomy with complete gross resection of an wxophytic mass. Light microscopic analysis shown numerous rhabdomyoblasts in various stages of embryogenesis, with cytoplasmic concentric fibrils, marked nuclear pleomorphism, mitotic activity and multinucleated cells. The tumor cells revealed focal positivity for desmin and muscle-epecific actin, whereas staining for S-100 protein was totally negative in the immunohistochemical studies. The final diagnosis was embryonal/pleomorphic rhabdomyosarcoma of the bladder. Neither radiation therapy nor chemotherapy was performed. The small number of cases of urinary bladder sarcoma in the adult reported in the literature makes it difficult to procedure an appropriate protocol for the approach to this tumor. Recently, the adoption of a uniform sarcoma staging system based on tumor grade, size, depth of invasion and presence or absence of metastic disease has been proposed, but further studies are required to confirm its usefulness