Recurrent solitary fibrous tumor of the pleura with malignant transformation.

Recurrent solitary fibrous tumor of the pleura with malignant progression occurs rarely. We report a case of solitary fibrous tumor of the pleura in an 85-year-old white woman that recurred 4 times during a span of 10 years and subsequently underwent malignant transformation. The accurate diagnosis of solitary fibrous tumor is aided by ancillary techniques, such as immunohistochemical staining; however, with malignant transformation, such tools may be of limited value. Long-term clinical follow-up is recommended for all patients with solitary fibrous tumor because of the potential adverse biological behavior of this tumor, which may lead to repeated recurrences and/or malignant transformation.