Cervical thymic cysts are a rare cause of neck masses in children. This case report describes a three-year-old child with a several-month history of an enlarging neck mass, who was emergently admitted due to airway obstruction. Computed tomography revealed a large cystic mass extending from the oropharynx to the level of the mediastinum. Excision of the mass with pathologic examination revealed a thymic cyst. The clinical picture, the theories regarding development of these cysts, as well as surgical options for treatment, are discussed.
