Hemangiopericytoma of the skull base and Collet-Sicard syndrome: a case report.

Hemangiopericytoma (HP) is a mesenchymal tumor that originates from the pericytes of the capillary walls. This is a rare neoplasm, particularly in the head and neck; the skull base is involved exceptionally. We report a case of a large HP located in the jugular foramen. The last four cranial nerves were involved, causing a Collet-Sicard syndrome associated with facial palsy. Only one case of HP and Collet-Sicard syndrome is reported in the literature. The clinical course of the disease is described, emphasizing the long period of elapsed time between onset of the complaints and the final diagnosis. Diagnostic procedures and immunohistochemical evaluation are analyzed, along with the possible differential diagnosis with other pathological processes that more frequently involve the jugular foramen.