Haemangiopericytoma: a clinical and radiological comparison with atypical meningiomas.

A small number of haemangiopericytomas (HPCs) are compared with a group of cases labelled as atypical meningiomas (AMs) extracted from our records over a 10-year period. There was close convergence between the two groups in terms of clinical presentation. Radiologically, they were quite different. HPCs subjected to angiography demonstrated a major vascular supply from branches of the internal carotid or vertebral arteries, whereas this was not a feature of the meningioma group. Half the HPCs arose from the lateral petrosal attachment of the tentorium; all the meningiomas were parasagittal. The HPCs did not prove to be more formidable technical challenges than the meningiomas: the operative blood loss was much the same in both. The same number of recurrences and deaths occurred in the two groups at approximately the same interval during the follow-up period, making both conditions equally grave in terms of prognosis.