99mTc-MIBI Positive of Cervical Ectopic Thymoma Case Report and Literature Review

The thymus originates from the third and fourth pharyngeal sacs. The thymus migrates from the neck to the mediastinum during the embryonic period. Ectopic cervical thymoma (ECT) is an extremely rare type of neck tumor that occurs mainly due to the inability of the embryonic thymus to fall sufficiently. Our department had admitted a case of ECT patients. The patient found a tumor in the neck for 1 year. The tumor appeared progressively increased for 3 months. Neck ultrasound, CT and 99mTc-MIBI imaging before surgery failed to determine the origin of the tumor. Pathologically confirmed as type AB thymoma after surgery. It is reported as follows.