Malignant transformation in solitary fibrous tumor of the pleura.

A 55-year-old man with a solitary fibrous tumor of the pleura on the left side underwent resection, but 2 recurrent tumors were found 3 years later. The recurrent tumors were reported to have undergone malignant transformation. Recurrent solitary fibrous tumor of the pleura with malignant progression is rare. Solitary fibrous tumor of the pleura often has an indolent clinical course, and may be asymptomatic for several years, so postoperative surveillance may necessitate long-term follow-up because of the potentially malignant transformative biological behavior of this type of tumor.