Thyroid Hemiagenesis: Narrative Review and Clinical Implications

Omotara Kafayat Lesi; Ankur Thapar; Nikhil Nanjappa Ballanamada Appaiah; Muhammad Rafaih Iqbal; Shashi Kumar; Dale Maharaj; Abdalla Saad Abdalla Al-Zawi; Shiva Dindyal

doi:10.7759/cureus.22401

Thyroid Hemiagenesis: Narrative Review and Clinical Implications

Cureus. 2022 Feb 20;14(2):e22401. doi: 10.7759/cureus.22401. eCollection 2022 Feb.

Authors

Omotara Kafayat Lesi¹, Ankur Thapar², Nikhil Nanjappa Ballanamada Appaiah³, Muhammad Rafaih Iqbal³, Shashi Kumar³, Dale Maharaj⁴, Abdalla Saad Abdalla Al-Zawi^{5

6

7}, Shiva Dindyal²

Affiliations

¹ General and Colorectal Surgery, Basildon and Thurrock University Hospitals, Mid and South Essex NHS Foundation Trust, Essex, GBR.
² Vascular Surgery, Basildon and Thurrock University Hospitals, Mid and South Essex NHS Foundation Trust, Essex, GBR.
³ Colorectal Surgery, Basildon and Thurrock University Hospitals, Mid and South Essex NHS Foundation Trust, Essex, GBR.
⁴ Vascular Surgery, Caribbean Vascular & Vein Clinic, Port-of-Spain, TTO.
⁵ General and Breast Surgery, Mid and South Essex University Hospital Group, Basildon, GBR.
⁶ General and Breast Surgery, Basildon and Thurrock University Hospitals, Mid and South Essex NHS Foundation Trust, Essex, GBR.
⁷ General and Breast Surgery, Anglia Ruskin University, Chelmsford, GBR.

Abstract

Thyroid Hemiagenesis (THA) is an uncommon, congenital anomaly defined by the absence of one thyroid lobe with or without the isthmus. Reports suggest it may be found more often in regions endemic for hypothyroidism. Genetic abnormalities are thought to have a role based on findings in monozygotic twins. Most cases are sporadic, however familiar clusters have also been documented. It is found more frequently in females. A majority of patients report no symptoms and THA is found incidentally during investigations or intraoperatively. THA is usually associated with normal thyroid function, but it can present with thyroid hypofunction. Since a majority of patients are asymptomatic, there are no specific recommendations for management. Ultrasound imaging and thyroid scintigraphy using technetium or iodine are useful in diagnosis. Its clinical importance occurs when the remnant thyroid lobe requires excision leading to the lifelong requirement for thyroxine supplementation. Published English literature (Medline, PubMed, and Embase databases) was searched. Medical subject headings (MeSH) terms used were "thyroid hemiagenesis," "one thyroid lobe," and "thyroid aplasia". Case reports, case series, and original articles were selected to provide a framework for this review. Articles reviewed were published in the past 20 years. The association of THA with thyroid cancer was explored. In this group, the F:M ratio was 3.25:1. Left THA constituted 53% of cases, right THA in 29.4%, and isthmus absence in 17.6% of cases. Also, the authors investigated the link between THA and hyperparathyroidism, both left and right THA are seen in an equal number of cases in the hyperparathyroidism subgroup. In patients with THA and Grave's disease, left THA was seen in a majority of cases (86.7%), while an equal number of left and right THA was observed in patients with Hashimoto's thyroiditis. In addition, congenital abnormalities associated with THA were observed, the left THA was seen in 60% and right THA in 40% of cases of this subgroup. The summative review provided a detailed insight into the epidemiology, aetiopathogenesis, genetics, symptomatology, diagnosis, and treatment for THA by combining findings and results from almost a hundred research papers from around the world. THA remains a poorly understood, often incidentally detected, abnormality in euthyroid patients undergoing investigations and treatment for other thyroid disorders.

Keywords: one lobe thyroid; thyroid aplasia; thyroid cancers; thyroid dysgenesis; thyroid hemiagenesis.

Publication types

Review