[Hemangiopericytoma of the petrous bone. Considerations apropos of 5 surgically treated cases].

5 cases of infratentorial hemangiopericytomas involving petrous bone are described. They show significant tendency to invade and destroy the bony base reaching into the soft parapharyngeal tissue of the neck. Radiography, tomography and CT scan of the skull demonstrate a large erosion of the petrous bone. At CT scan the lesion appears slightly hyperdense with marked enhancement. Selective angiography shows an important vascular supply from the external carotid artery, the deep and ascending cervical arteries and the extracranial part of the vertebral artery. Embolisation or surgical occlusion of the branches of external carotid artery and cervical arteries are useful to reduce bleeding during biopsy. Radiotherapy is advisable.