[Solitary fibrous retroperitoneal tumour: report of two cases].

Solitary fibrous tumours are benign tumours, described for the first time by Klemperer and Rabin in 1931. They are mesenchymal tumours which usually arise in the pleura, while retroperitoneal sites have been rarely described. The authors report two cases of very large retroperitoneal tumours in two men aged 58 and 47 years, respectively, who consulted for abdominopelvic vaulting associated with gastrointestinal and urinary disorders. Ultrasound-guided biopsy suggested the diagnosis preoperatively in one case. In the light of these cases, the authors present a review of the main extrapleural sites described to date, as well as the most characteristic radiological, histological and immunohistochemical features in order to facilitate the diagnosis.