Trigeminal pain caused by a parapontine epidermal cyst.

A case of trigeminal neuralgia caused by a parapontine epidermal cyst is reported. The trigeminal inlet zone at the pons was completely surrounded by the tumor. No vascular element was detected around the trigeminal nerve root. Neurological symptoms were completely normal except for typical tic douloureux. Pain was controlled initially by carbamazepine, later by radiofrequency trigeminal nerve coagulation, and finally by microsurgical decompression. Review of the literature suggested the importance of lesions of the middle fossa as another etiological factor. When surgery is performed by the posterior route, the possibility of overlooking these lesions may exist.