Thyroid hemiagenesis: description of two clinical cases, anatomical review, and critical synthesis of the literature

Introduction: Thyroid hemiagenesis (THA) is a rare congenital thyroid condition in which one of the lobes gland fails to develop. The etiology remains uncertain, with main hypotheses suggesting genetic alterations embryogenesis associated failure descend its final position. Additionally, may be present both asymptomatic and euthyroid patients, as well those diseases such hyperthyroidism, nodular goiter, neoplasia. Objective: To critically review literature on subject, detailing known aspects anatomy THA, demographic findings patients this condition, while also adding two case reports literature. Methods: An extensive, systematized MEDLINE database was carried out using descriptor “thyroid hemiagenesis”. A total 214 related articles up October 2022 were retrieved. Out these, 154 described new cases contained epidemiological data reported patients. Studies without reports, systematic reviews, lacking or available data—rendered inadmissible for review—were excluded from analysis. Results: Our identified following prevalence characteristics: 520 THA reported, 50 them, absence isthmus coexisted. Several conditions statuses have been gland. Conclusion: more prevalent female, young, Although rare, it vital head neck surgeons aware possibility, thereby avoiding unnecessary manipulation absent bed and, consequently, preventing complications.