Malignant solitary fibrous tumor of the pleura.

We describe a case of malignant solitary fibrous tumor of the pleura in a 15-year-old female who presented clinically with back pain. Grossly, the tumor had a pedicle attached to the pleura and histologically showed proliferating spindle-shaped cells with a high mitotic index. Immunohistochemical and ultrastructural features were consistent with a tumor of fibroblastic origin. Flow cytometric DNA analysis revealed an aneuploid population among the tumor cells.