Recurrent retroperitoneal solitary fibrous tumor: a case report and review of the literature

Background: Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm described initially in visceral pleura but can occasionally involve other sites such as the urinary tract. Extrapleural localizations are often indolent but some malignant SFTs have been described. The treatment and the most important prognostic factor for SFT seem to be complete resection of the neoplasm. Case report: We report the 10-year history of a retroperitoneal SFT, which recurred twice after conservative management, and was eventually treated with en bloc resection of the mass, the bladder, and the prostate, and urinary diversion by ileal conduit. To our knowledge, this case has the longest follow-up in the literature. Conclusion: Extrapleural SFTs often have indolent but unpredictable behavior as they can recur even after many years. Some histologic features are associated with the malignancy of these tumors. Complete resection of the neoplasm is the most important prognostic factor. Patients with SFT should be considered for a very long follow-up after the surgery due to the risk of possible late recurrences.