Cervical Thymic Cysts

A review of cervical thymus cysts and a case report are presented. This benign lesion was, as in most cases previously reported, situated laterally on the neck, deep to the anterior border of the sternocleidomastoid muscle and thus simulating a common branchial cyst preoperatively. But unlike the latter most cases of cervical thymus cysts are recognised during childhood. They are believed to develop in remnants of thymic tissue which have failed to descend from the third branchial pouch into the mediastinum in the 6th to 8th week of embryonic life.