Epidermoid cyst mimicking a thyroglossal duct cyst in a pediatric patient: a case report.

This article presents a case of an epidermoid cyst that mimicked a thyroglossal duct cyst in a pediatric patient. An 8-year-old boy was referred for evaluation of a volumetric increase in the median cervical region with an evolution of about 4 years. The skin in the submental region was healthy and normal colored. Palpation revealed a mobile, well-circumscribed nodular lesion of soft consistency. Computed tomography of the neck showed an expansive hypodense formation extending from the base of the tongue to the upper portion of the hyoid bone, suggesting a thyroglossal duct cyst. Considering the diagnostic hypothesis, cystic enucleation via the Sistrunk procedure was planned. However, no ductal structure was identified during the surgical procedure, and the lesion was only near, but not attached to, the hyoid bone. Simple excision of the lesion was therefore performed. At the most recent follow-up examination, about 3 months postoperatively, the patient demonstrated satisfactory clinical progress. The epidermoid cyst close to the hyoid bone presented diagnostic difficulty due to its similarity to a thyroglossal duct cyst. Computed tomography provides limited information for diagnosing this type of lesion, and ultrasonography is the preferred test. In view of the uncertain diagnosis in this case, the extent of the excision was determined during the surgery, and simple excision was a satisfactory treatment associated with a good prognosis.