SECTION EDITOR: EDWARD B. STELOW, MD
Diagnosis: Ectopic intrathyroidal thymic tissue
Cervical ectopic thymic tissue has been reported to be a rare cause of neck masses in children.1,2 The true incidence of ectopic thymic tissue is unknown because it rarely produces symptoms and often is found incidentally. When detected preoperatively, thymic tissue is not often suspected and is more often diagnosed as tumor, branchial cleft cyst, cervical lymphangioma, or cervical teratoma.3 Similarly, ectopic thymic tissue within the thyroid gland has previously been thought to be rare and is therefore seldom considered in the differential diagnosis of thyroid lesions. However, given the embryological course of development of these organs, the incidence may be higher than previously believed.
Pathology Quiz Case 1: Diagnosis. JAMA Otolaryngol Head Neck Surg. 2013;139(1):88. doi:10.1001/jamaoto.2013.1125b