Submental midline dermoid cyst in a 25-year-old man.

A 25-year-old man presented with a painless, nontender, nonerythematous sublingual mass that had gradually increased in size over the preceding 2 years. Fine-needle aspiration biopsy was nondiagnostic. During the week following our evaluation, the mass became increasingly painful and swollen, and it severely impaired his speech and swallowing. Magnetic resonance imaging demonstrated a sharply demarcated, fluid-filled, sublingual cyst that measured approximately 7.1 x 4.5 x 2.9 cm. During surgical excision, the mass was found to contain a large amount of sebaceous material, which was removed along with the entire capsule of the cyst. Histologic examination of the cystic contents identified epidermis, sebaceous glands, and hair follicles along with copious sebaceous material. These findings are consistent with a dermoid cyst.