Malignant solitary fibrous tumor of the urinary bladder.

A 67-year-old man was examined for persistent pain over his lower abdomen and was found to have a large pelvic tumor. During surgery, we detected a 16 × 9 × 9 cm(3) urinary bladder tumor with small intestinal adhesions, and performed partial cystectomy and segmental resection. Histological and immunohistochemical examinations established the diagnosis of malignant solitary fibrous tumor (SFT). Only 10 cases of urinary bladder SFT have been reported in the English literature; our patient is the second one with malignancy and had a longer follow-up period than the other case.