Solitary fibrous tumor of the spinal cord: a clinicopathologic study of two cases.

Two cases of solitary fibrous tumor of the spinal cord are described. The patients were two men, 36 and 47 years old. Clinically, they sought medical care because of progressive paresthesias or urinary incontinence caused by a nodular, fairly circumscribed intraspinal tumor of the cervical and thoracic spinal cord, respectively. Preoperative magnetic resonance images suggested meningioma. In both cases, laminectomy with tumor resection was carried out. Microscopically, the tumors featured short spindle cells haphazardly enmeshed in a collagenized ground substance. No atypia, necrosis, or significant mitotic activity was recognized. Tumor cells were positive for CD34, bcl2, vimentin, and, in one case, CD99. Both patients recovered from symptoms and are alive and well 12 and 18 months, respectively, after surgical resection. The differential diagnosis includes meningioma, schwannoma, and hemangiopericytoma, all of which may occur in the spinal canal. A careful morphologic approach and the judicious use of immunohistochemistry may assist in distinguishing among these conditions, although some irreducible difficulties may be posed by hemangiopericytoma. Although solitary fibrous tumor of the spinal cord presents with fairly comparable clinical, instrumental, and pathologic patterns, we believe that compilation of more cases is needed to segregate it as a distinct clinicopathologic entity.