Abstract
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.