Primary mediastinal hemangiopericytoma with fatal outcome in a child.

Hemangiopericytoma occurs infrequently in children, and mediastinal sites are exceedingly rare. We report a case of mediastinal hemangiopericytoma in a 4-year-old child, which resulted in the patient's death due to large size, anatomic location, and associated perioperative bleeding. The pathologic diagnosis was established on the basis of light microscopic, immunohistochemical, and electron microscopic features. The presentation and clinical course of this case contrast with those of congenital or infantile hemangiopericytoma, which generally has a favorable outcome. Hemangiopericytoma should be considered in the differential diagnosis of large mediastinal masses in children.