Background: Dermoid cysts in the floor of the mouth are relatively uncommon developmental lesions. They are thought to arise in the midline and along the lines of embryonic fusion of the facial processes containing ectodermal tissue.
Case report: A 17-year-old female presented with a 3-month history of a growing, progressive swelling in the mouth floor. Clinical examination revealed a rather large symmetrical, soft swelling in the mouth floor, displacing the tongue superiorly. The fast growing nature and size of the lesion raised suspicion of potential compromise to the airway. Surgical excision was therefore performed.
Conclusion: Differential diagnosis of cystic lesions in the floor of the mouth is of paramount importance, as the recommended surgical techniques vary depending on the anatomical position of the lesions. The intraoral approach is preferred for those lesions that do not extend beyond the mylohyoid muscle boundaries; this leads to a satisfactory cosmetic and functional outcome.
Keywords: Dermoid Cyst; Diagnosis; Differential; Mouth Floor; Oral; Surgery.