Malignant mesenchymoma of the bladder

A case of malignant mesenchymoma of the bladder, containing fibroleiomyomatous, myxomatous, osteoid, and cartilaginous components is presented. The primary pedunculated tumor measuring 18 X 10 X 9 cm and weighing 934 g, arose from the anterior wall of the bladder and was treated by partial cystectomy. Six months after surgery, cystoscopy revealed a recurrent tumor situated at the dome of the bladder. The patient received surgery, chemotherapy, and irradiation for recurrent tumor, but died of the disease 21 months after the first operation. Autopsy revealed extensive local recurrence with wide-spread metastases of malignant mesenchymoma of the bladder and an incidental finding of coexisting clear cell carcinoma in the right kidney (pTl, NO, MO). There have been no previous reports of association of malignant mesenchymoma of the urinary bladder and renal cell carcinoma.