ARACHNOID CYSTS OF THE POSTERIOR-FOSSA

The clinical symptoms and signs of 4 patients with arachnoid cysts in the posterior fossa are discussed. In 3 patients, the cyst was in the internal auditory canal; 1 patient had an acoustic neuroma and 2 large cysts in the cerebellum. Whereas the conventional diagnostic tests for acoustic neuroma cannot differentiate between neuromas and arachnoid cysts, the newer thin section body scanners can show a lesion with no enhancement in the case of the cyst. Surgical approaches for removal of this lesion must take into consideration the preservation of hearing in the involved ear.