Trigeminal schwannoma associated with pathological laughter and crying.

A 46 year old man with trigeminal schwannoma displayed symptoms of ataxia with pathological laughter and crying. The tumour developed in the cerebellopontine angle, compressing the pontomesencephalic structures backward, extending in the posterior parasellar region and Meckel's cave. No recurrence of laughter and crying attacks were noted after total removal of the tumour. Theories of mechanism of pathological laughter and crying reported in the literature are reviewed.