[Increased intracranial pressure caused by obstruction of torcular herophili with hemangiopericytoma: a case report].

A 49-year-old male had experienced diplopia for half a year. The intracranial pressure was markedly elevated (450 mmH2O). Neuroimaging revealed a tumor incompletely occluding the torcular herophili and the bilateral transverse sinuses without cerebral or cerebellar compression by the tumor. Both cortical veins and cervical veins were enlarged, and the Sylvian vein and Rabbe's vein and the tentorial sinus were collateral vessels. Biopsy was performed and histologic examination proved hemangiopericytoma. The patient underwent Gamma-knife treatment and the tumor decreased in size 3 months after the treatment.