[Extensive dermoid cyst occupying almost the entire floor of the mouth in a juvenile patient].

This article presents a case report of a 15-year-old female patient with an substantial swelling of the floor of the mouth and the submandibular region with impairment of deglutition and speech. Descriptions of the diagnostic and operative procedures are given. The histological examination revealed the typical pattern of a dermoid cyst but such dimensions are rare. Complete removal is necessary to prevent fulminant inflammation and disorders of function; furthermore the risk of a malignant transformation is seldom but present.