[Retroperitoneal solitary fibrous tumor: a case report]

A 63-year-old man with a retroperitoneal tumor found incidentally was referred to our hospital. Computed tomography showed a tumor ventrally adjacent to urinary bladder and prostate. Pathological examination of retroperitoneal tumor specimens obtained by percutaneous needle biopsy revealed hypercellularity of spindle cells positive for CD 34. Under the suspicion of solitary fibrous tumor (SFT) or stromal tumors of uncertain malignant potential (STUMP), we performed en bloc resection of tumor, urinary bladder and prostate because tumor was firmly fixed to urinary bladder and prostate. The final diagnosis of retroperitoneal tumor was SFT because pathological findings of the surgical specimen were the same as those of the biopsy specimens.