Pathological laughter in trigeminal schwannoma: case report and review of the literature.

Pathological laughter is an uncommon manifestation of neurosurgical diseases. Very few cases of trigeminal schwannoma have been reported in the literature presenting with pathological laughter as a predominant symptom. We are reporting on a case of multi-compartmental trigeminal schwannoma presenting as pathological laughter and discuss a review of the literature. A 23-year-old lady presented with pathological laughter, along with symptoms pertaining to other cranial nerves and cerebellar dysfunction. Magnetic resonance imaging (MRI) of the brain was suggestive of a dumbbell-shaped mass in the middle and posterior cranial fossa on the left side, causing significant compression of the pons. She was investigated and operated for multi-compartmental trigeminal schwannoma. Following surgery, abnormal laughter disappeared immediately and no recurrence of symptoms was -present for a follow-up of 16 months. This case supports the role of the brainstem, especially the pons, in the control of laughter and, perhaps, of the medial temporal lobe too.