Solitary fibrous tumor of filum terminale.

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that most commonly arises from the visceral or parietal pleura. Solitary fibrous tumor with a primary site in the filum terminale has not been reported previously in the literature. Here we report a case of SFT occurring in the filum terminale. The characteristic imaging feature of this tumor is hypointensity on T2-weighted images. Even though rare, SFT should be considered in the differential diagnosis of tumors occurring intraspinally, even in the filum terminale.