Cervical thymic cyst: report of a case and review of the literature.

Congenital thymic cysts are uncommon and often misdiagnosed as either branchial cleft or cystic hygromas. This paper presents the case of a male child, who presented with a soft, fluctuating mass in the left side of his neck. Surgical excision revealed an ectopic thymic cyst. The histopathologic features of thymic cysts are diagnostic. Ectopic thymic tissue may be an infrequent finding, but it should be included in the differential diagnosis of neck masses, especially in children.