Infant ectopic cervical thymus one case report: diagnostic and management difficulties.

Cervical ectopic thymus (CET), an embryological anomaly detected incidentally at autopsy, is rarely described in clinical patients. Furthermore, aberrant cervical thymic tissue is an infrequently reported cause of neck masses, and especially for pediatric patients. However, according to clinical work, it should be included in the differential diagnosis of neck masses, particularly for children patients. Thymic tissue rests can be found all along the route of thymic descent from the neck into the anterior mediastinum. In routine practice, the preoperative diagnosis of ectopic cervical thymus is seldom considered and it is often misdiagnosed as a possible tumor or as a lymph node, which leads to biopsy or surgical removal. Here, a case of ectopic thymic tissue was presented in the neck misdiagnosed as cystic hydroma (one type of lymphatic malformation). Our misdiagnosis was introduced, the literature about diagnosis and management controversy were reviewed in recent years.