The unusual case of a ventral brain stem schwannoma located at the ent
ry zone of the hypoglossal nerve in a 49-year-old woman is reported. T
he diagnosis of a schwannoma was confirmed histologically after partia
l tumor resection via the dorsolateral, suboccipital, transcondylar ap
proach. Hypotheses for the pathogenesis of intramedullary schwannomas
are discussed.