[Dermoid cyst of the floor of the mouth].

Dermoid cysts are congenital lesions composed of tissues with different origins: ectoblastic, mesoblastic, or endoblastic, caused by a defect in the fusion of the embryonic lateral mesenchymatic mass. A true dermoid cyst is a cavity covered with epithelium showing keratinisation and presenting identifiable dermal appendices. We present a case of a male patient aged 53 years presenting tumouration on the floor of the mouth with an evolution of about 30 years. A bibliographic revision of this pathology is also presented.