Lateral dermoid cyst of the floor of the mouth.

Dermoid cysts are the developmental cysts that occur in the head and neck. The vast majority of dermoid cysts of the floor of the mouth (DCFOMs) are located in the midline; which is the second most common site of these cysts in the head and neck region. This case report describes a unilateral dermoid cyst in the floor of the mouth in a 19 years old Saudi girl. This lesion appeared as a left sublingual doughy swelling of 2 months duration which elevated the tongue and caused difficulty in eating. Surgical excision was done through oral approach. The histopathology examination confirmed the diagnosis of a dermoid cyst having characteristic stratified squamous epithelial lining and focal skin adenexa in the subepithelial tissue. The patient has been followed up for 28 months without any recurrence.