Ectopic intrathyroidal thymus tissue is rare. Mostly it is seen in childhood as an asymptomatic thyroid nodule. It can be easily misdiagnosed as a benign or malignant thyroid nodule. Like thymus, it may regress in time. Ectopic thymus tissue can rarely develop to thymoma or thymic carcinoma. Intrathyroidal ectopic thymus tissue has similar sonographic features to thymus and should be kept in mind to avoid unnecessary diagnostic and surgical intervention.
Ectopic thymus, intrathyroidal thymus, thyroid nodule, ultrasonography