Postoperative recurrence solitary fibrous tumor of the pelvic with malignant transformation.

A 48-year-old man with a solitary fibrous tumor of the pelvic underwent resection, but recurrent tumor was found 4 years later. Recurrent solitary fibrous tumor of the pelvic with malignant progression is rare. Solitary fibrous tumor of the pelvic often has an indolent clinical course, so postoperative surveillance may necessitate long-term follow-up because of the potential adverse biological behavior of this tumor, which may lead to repeated recurrences and/or malignant transformation.