Hemangiopericytoma of the spinal canal. Report of three cases.

Hemangiopericytoma is a vascular neoplasm consisting of capillaries outlined by an intact basement membrane that separates the endothelial cells of the capillaries from the spindle-shaped tumor cells in the extravascular area. These neoplasms are found in soft tissues but have rarely been shown to involve the spinal canal. This is a report of three such cases. Surgical removal of the tumor from the spinal canal was technically difficult. A high risk of recurrence has been reported but in these three cases adjunctive radiotherapy appeared to be of benefit in controlling the progression of the disease. These cases, added to the six cases in the literature, confirm the existence of hemangiopericytoma involving the vertebral column with extension into the spinal canal. This entity should be included in the differential diagnosis of lesions of the spinal canal. The risk of intraoperative hemorrhage should be anticipated.