As a result of the teaching of the anatomist, many physicians have the concept that the thyroid gland is a symmetrical structure. However, observant surgeons have long recognized that asymmetry is more common, and that the right lobe is usually longer than the left. This observation can readily be confirmed by physicians experienced with thryoid scanning. Thyroidal hemiagenesis is simply an extreme degree of asymmetry. Once again, it is usually the right lobe that persists. However, the failure of an entire thyroid lobe to develop is an extremely uncommon anomaly. The authors have encountered this entity only four times in an experience with scans on over 7,000 thyroid patients.
Our most recent patient had a thyroid carcinoma in the center of the hyperplastic hemithyroid. Review of the literature revealed almost no references to the entity of thryoidal hemiagenesis. Furthermore, the association of a carcinoma of the thyroid would seem to
Hamburger JI, Hamburger SW. Thyroidal HemiagenesisReport of a Case and Comments on Clinical Ramifications. Arch Surg. 1970;100(3):319-320. doi:10.1001/archsurg.1970.01340210095026