Cystic masses of the head and neck region related to primitive foregut development are rare lesions found in the newborn infant. These lesions are usually localized to the tongue, floor of mouth, and anterior neck, and they may cause significant airway obstruction in the neonate. These developmentally derived cysts are essentially normal cells in an abnormal location and are considered to be a type of heterotopia. Three general mechanisms can account for these developmental anomalies: (1) failure to resorb embryologic structures, which leads, for example, to persistence of the thyroglossal duct; (2) errors in migration, which are believed to cause accessory spleens; and (3) heteroplasia, or aberrant