Sublingual Dermoid Cyst: A Diagnostic Challenge During Clinical Examination

Introduction: Epidermoid cysts are benign lesions that may occur in many different sites of the body. They are classified into 3 types: epidermoid cysts when the lining presents only epithelium, dermoid cysts when skin adnexa are found, and teratoid cysts when mesodermal elements are present. Case Presentation: A 13-year-old boy presented with a gradually enlarging sublingual mass over a period of 4 years. The mass was painless at start but in the last 3 months, it was associated with pain and difficulties during eating and dysarthria. The general examination was unremarkable and examination of the oral cavity showed a 5∗6 cm mass in the right side of the tongue and within the tongue. The mass was soft and nontender, fluctuation was positive, there was no pulsation over the mass, transillumination was negative, and other parts of the oral cavity were normal. Neck examination was also normal with no enlargement of the cervical lymph nodes. Aspiration of the lesion showed turbid yellow fluid (keratin like substance) with no blood. Complete surgical excision of the cyst was done, which was dermoid cyst of the tongue containing hair and fat. The patient was discharged on the same day of surgery with no postoperative events. Conclusion: Dermoid cyst of the tongue is an extremely rare condition. High index of suspicion is required for the diagnosis. Aspiration of the cyst helps in the diagnosis due to the typical yellow color because of cholesterol contents. The prognosis is excellent after complete surgical excision.