Ectopic thymus presenting as a solid submandibular neck mass in an infant: case report and review of literature.

Solid ectopic cervical thymus is an extremely uncommon etiology of a neck mass in an infant. It occurs in the line of descent of the thymus from the angle of the mandible to the superior mediastinum. Nine cases of ectopic cervical thymus in infants have been reported in the literature. Only two of nine cases were solid, the remaining seven were thymic cysts. A preoperative diagnosis is seldom considered and is often misdiagnosed as a possible malignancy or a lymph node. We present a case of a 2-month-old infant with an asymptomatic enlarging right neck mass. Patient underwent complete excision of the mass.