Solitary fibrous tumour of the urinary bladder with expression of bcl-2, CD34, and insulin-like growth factor type II.

We describe a solitary fibrous tumour of the urinary bladder wall removed from a 50-year-old man with a history of pelvic pain, dysuria, and urinary bleeding. Anamnesis revealed a weight increase during the preceding 3 months, but no apparent episodes of biochemical hypoglycaemia or hormonal abnormalities. The patient is alive and well 18 months after surgery. Pathological examination revealed a 6.5-cm well-circumscribed nodular mass composed of uniform spindle cells arranged in bundles and fascicles with varying amounts of collagen and a typical haemangiopericytoma-like vascular pattern. The tumour cells were positive for bcl-2, CD34, and vimentin and ultrastructurally showed mesenchymal-myofibroblastic traits. These cells produced insulin-like growth factor type II mRNA as demonstrated by non-isotopic in situ hybridization. This rare case with a solitary fibrous tumor suggests that insulin-like growth factor type II could join CD34 and bcl-2 as markers for postoperative differential diagnosis.