[Dermoid, epidermoid and teratoma cysts of the tongue and oral cavity floor].

Most dermoid cysts in the oral cavity floor are derived from epithelial debris or rests, enclaved during midline closure of the bilateral first and second branchial arches. They may also result from ectodermal differentiation of multipotential cells, most likely pinched off at the time of anterior neuropore closure. Congenital epidermoid cysts and teratomata of the tongue may be explained in a similar manner. Only 6.9 per cent of dermoid cysts observed in humans involve the head and neck regions. Treatment consists in complete surgical removal, with excellent prognosis in cases free of complications. This is a report on a rare case of epidermoid cyst, described because of its unusual location and cell population variation of the epithelium lining the cystic cavity.