Solid ectopic cervical thymus in an infant: A case report

Introduction. Ectopic cervical thymus tissue results from incomplete migration of the thymic primordia during embryogenesis. It is asymptomatic in most of the cases, however, in 10% of patients there are different kind of symptoms. Case report. A 4-month-old boy was referred to our clinic, for the evaluation of a growing large neck mass on the right side that has been present since birth. Physical examination revealed a painless, soft, moderately mobile, and irregular round solid neck mass localized on the right side, in front of the sternocleidomastoid muscle, below the parotid gland, and above the carotid lodge. The mass was 40 x 32 x15 mm in diameter. Following the clinical, ultrasonographic and magnetic resonance imaging findings, we suspected that it was an ectopic cervical thymus. Surgical excision was done. The pathology report confirmed the presence of the ectopic cervical thymic tissue with Hassall?s corpuscles. The postoperative course was unremarkable and the wound healed well. Furthermore, clinical, immunological, and echography 6-month follow-up was unremarkable. Conclusion. The congenital cervical ectopic thymus is a rare congenital anomaly, however it should be considered in the differential diagnosis of neck masses.