Solitary fibrous tumor in the extremity: case report and review of the literature.

A solitary fibrous tumor is a relatively unusual neoplasm first described as a distinctive tumor arising from pleura. Some reports have shown that solitary fibrous tumors also affect extrathoracic regions. The current study presents a literature review with four additional patients with solitary fibrous tumor arising from the extremities to clarify clinicopathologic features. The current four patients were two males and two females, ranging from 17 to 60 years of age. Magnetic resonance imaging scans of the current patients showed inhomogeneous low to intermediate intensity signal on T1-weighted images and inhomogeneous intermediate to high intensity signal on T2-weighted images. Histologically, the tumors were composed of a haphazard proliferation of spindle cells, although cellularity was variable in each case. Two of the four tumors showed hypercellularity of spindle cells with focally myxomatous or hyaline changes, whereas myxomatous patterns with scattered spindle cells throughout the specimens were observed in the other two tumors. Immunohistochemically, all four patients showed positive immunoreactivity for CD34, and two tumors showed focally positive immunoreactivity for bcl-2 protein. During the followup of 12 to 54 months, neither local recurrence nor distant metastasis was detected after wide resection. Examination of the literature and the current patients suggests that solitary fibrous tumors in the extremities are likely to have a malignant potential, although most patients have a benign clinical course. Local wide resection and careful long-term followup are necessary for patients with solitary fibrous tumor in the extremities.