A Rare Case of Primary osteosarcoma of urinary bladder.

Extraskeletal osteosarcoma is a malignant mesenchymal soft tissue tumor without attachment to the bone, and is able to produce osteoid or cartilaginous matrix. This entity accounts for 1% of all soft tissue sarcomas. Thus far, less than 35 cases of bladder osteosarcomas have been reported in the literature. These tumors are associated with very poor prognosis. We report a case of primary osteosarcoma of the urinary bladder presenting with intermittent hematuria, dysuria, and right flank pain. Contrast-enhanced computed tomography scan of the abdomen, pelvis, and chest revealed a bladder mass and pulmonary metastases with specks of calcification.