Epidermoid/Dermoid (Dermoid Cyst)

Epidemiology

The term “dermoid cyst “ (DC) encompasses various benign germ cell masses. These lesions include epidermoid, dermoid, and teratoid cysts, of which epidermoids and dermoids are most common. Teratoid tumors are very rare. About 7% of DCs occur in the head and neck region. The majority of these lesions (65%) occur in orbital and nasal regions, whereas 24% arise in the oral cavity. There is no reported sex predominance for DCs.

Clinical Findings

The epidermoid variety usually presents at birth, whereas dermoids most commonly present in the second or third decade of life. Oral cavity DCs typically arise in the sublingual space. Other sites include the dorsum of the tongue, hard or soft palate, lips, and buccal mucosa. DCs are usually midline lesions.

The clinical presentation usually depends on the location with respect to the mylohyoid muscle. On physical examination, these lesions tend to have a doughy texture and may demonstrate pitting after palpation. Floor of mouth DCs often present as submucosal masses. These masses may be confused clinically with a ranula. Because these lesions may elevate the tongue, patients may present with difficulty swallowing. Submandibular DCs are located below the mylohyoid muscle. These lesions may present as an anterior neck mass. Because these lesions are not fixed to the tongue or hyoid bone, these lesions do not move when the tongue is protruded. This finding may be used to differentiate DCs from thyroglossal duct cysts.