A Pediatric Lateral Submental Mass: A Rare Presentation of Dermoid Cyst

Dermoid cysts are benign cutaneous neoplasms that contain germ cells from the ectoderm and mesoderm. Approximately 70% are diagnosed during childhood before the age of 5. Although they can present throughout the body, the prevalence is 7% for those arising from the head and neck. These lesions present primarily as midline masses and are classified as sublingual, submental, or overlapping depending on their relationship with the muscles of the floor of mouth. A 10-year-old female presented with a 2-week history of right submental swelling. She denied pain, dysphagia, odynophagia, or respiratory distress. Physical examination showed nontender fullness of the submental region without erythema or induration and no palpable cervical lymphadenopathy. Ultrasound showed an oval-shaped cystic mass measuring 4.8 x 4.0 x 2.6 cm. After a course of clindamycin, a computed tomography was obtained which showed a right 4.5 x 4.0 x 2.6 cm fluid filled lesion, within the right lateral floor of mouth. Intraoral resection was performed and the mass was freed from the geniohyoid and mylohyoid. Histopathology was consistent with a dermoid cyst. Submental masses have a broad differential, but rarely are they dermoid cysts if they arise lateral to the midline. With appropriate diagnosis and total surgical excision, patients and their families can be reassured in similar cases.