Solitary Fibrous Tumor of the Urinary Bladder: A Case Report

ABSTRACT

Solitary fibrous tumor (SFT) most commonly affects the pleura and these tumors have been recently reported to be found in unusual locations. We describe here a solitary fibrous tumor of the urinary bladder that was removed from a 79-year-old man having a history of gross hematuria and dysuria. Transabdominal ultrasonography showed a huge soft tissue mass in the urinary bladder. The cut surface of the tumor showed a grayish-white, hemorrhagic and gelatinous appearance. Necrosis was not found. Microscopically, the tumor showed a proliferation of spindle or ovoid cells that were intervened by a collagenous stroma. A variety of growth patterns was identified but the so-called patternless pattern was the predominant one. The spindle cells had almost no mitotic figures, and there was very little or no nuclear atypia. Immunohistochemical stains showed a strong reactivity for CD34 and a focal reactivity for bcl-2. The ultrastructure of the tumor cells showed mesenchymal-myofibroblastic traits.