Primary solitary fibrous tumor of the retroperitoneum.

Solitary fibrous tumor is an uncommon neoplasm affecting adults and typically located in the pleura and can also occur in a large number of other extra thoracic sites. We present the case of a solitary fibrous tumor (SFT) of the retroperitoneum and describe their histopathological and immunohistochemical features. The identification of SFT in the retroperitoneum is of importance because its clinico-pathological behaviour is still unclear. The pathologist plays a fundamental role in establishing both the positive and differential diagnosis.