Cystic trochlear nerve neurinoma mimicking intrinsic brainstem tumour.

Trochlear nerve neurinomas are very rare with less than 20 surgically proved cases reported in the literature. A case of histologically proved cystic trochlear nerve neurinoma, which was mimicking an intrinsic brainstem tumour is reported here. The tumour was totally excised. The clinical features and surgical management are described and the literature reviewed.