Intracranial trigeminal nerve rhabdomyoma/choristoma in a child: a case report and discussion of possible histogenesis.

Rhabdomyomas are rare tumors that usually arise within the heart, orocervical, or vulvovaginal regions. The cardiac tumors have a characteristic immature morphology, occur often in association with tuberous sclerosis, and are regarded as hamartomas rather than true neoplasms. The histogenesis of the extracardiac tumors and their true neoplastic nature are matters of controversy. We report the first case of a rhabdomyoma located inside the cranium. The intimate association with the mandibular division of the trigeminal nerve, the normal embryogenesis of the craniofacial muscles, and animal homograft and xenograft experiments provide a framework for considering this tumor, and possibly other rhabdomyomas, as a choristoma/hamartoma rather than a true neoplasm.