Giant solitary fibrous tumor of the pelvis: A case report and review of literature.

• Extrathoracic SFTs are not common, our case is a rare pelvic localization of this disease. • The pre-operative diagnosis is difficult because clinical symptoms, physical examination and imaging are not diagnostic. • SFT should be considered in the differential diagnosis of any mesenchymal lesion arising from the gastrointestinal tract. Solitary fibrous tumors (SFTs) are rare spindle cells neoplasms most likely arising from mesenchymal cells. Usually they involve the pleura. Even if extra-thoracic SFTs are rare, lately they are diagnosed with increased frequency. We describe the case of giant pelvic and retroperitoneal neoplasm, a rare solitary fibrous tumor, in a 51-year-old man that was admitted for abdominal pain. On CT a SFT appears usually as a smooth, lobulated mass with occasional calcifications, but the imaging differential diagnosis with other mesenchymal tumors is very difficult, if not impossible. The histological and immune-histochemical features of SFTs are helpful for the differential diagnosis. The malignant potential of this cancer is low, but it is very important to perform an optimized surgery and a close follow up in the patient. We believe that this case is particularly interesting and complex because of the difficulty of predicting the future biological behavior. [ABSTRACT FROM AUTHOR]