Congenital dermoid cyst of the tongue.

True dermoid cysts of the oral cavity are rare, usually presenting as midline swellings in the floor of the mouth and occasionally elsewhere in the oral cavity. This report describes the diagnosis and management of a congenital dermoid cyst of the lateral aspect of the body of the tongue in a 10-year-old girl. The theories of the pathogenesis of this cyst during embryogenesis of the tongue are also reviewed.