A huge retroperitoneal solitary fibrous tumor

Abstract Solitary fibrous tumors (SFTs) are infrequent fibrous neoplasms that arise most commonly in the thoracic cavity. Although initially described as arising from the pleura, SFTs have been reported at a wide range of anatomic sites. Owing to their rarity, accurate diagnosis of SFTs remains a challenge for clinicians. A 38-year-old man presented complaining of difficulty in defecation and a progressive perineal mass. A computed tomography scan revealed a huge pelvic mass characteristic of central necrosis and calcification with a severely compressed adjacent rectum. Magnetic resonance imaging demonstrated a well-delineated mass with a maximal diameter of 15 cm. During surgery, an encapsulated tumor was excised via simultaneous abdominal and perineal approaches because of its huge size. SFT should be kept in mind for differential diagnosis of retroperitoneal tumors.