A case of extrapleural solitary fibrous tumor of the thigh with eight years follow-up.

: Solitary fibrous tumor (SFT) is a rare neoplasia. Now classified as SFT, it was first described in 1942 as "hemangiopericytoma" (HPC), and its origin was supposed to be the pericytes. The location outside the pleura is considered uncommon and the tumor situation on the thigh is much more unusual. In this article, we present a case of a SFT located in the hip. Even if the limb situation of the SFT is considered rare, some tumors in lower limb were reported in the past few years. Our initial clinical diagnosis, in this case, was a variant of lipoma (fibrolipoma), so no further investigations were performed before surgery at that time, and the surgery was planned as a simple procedure. The mimics of SFT with a large variety of benign tumors, especially in long-term evolution cases, make the preoperative diagnosis much more difficult. After the excision of the tumor and histological and immunohistochemical (IHC) tests, the diagnosis was finally stated. Even the findings in the exam conducted us to a most likely benign evolution, the eight years follow-up allowed us to strongly correlate the evolution with laboratory findings in this case. Further follow-up in this case can and will be performed.