Thyroid hemiagenesis: a case series and review of the literature

PurposeThe purpose of this study is to present a case series and review recommendations within the literature concerning thyroid hemiagenesis.Materials and MethodsThis is a (1) retrospective case series review of 5 patients and (2) literature review (using Medline) on thyroid hemiagenesis.ResultsMost reported cases are female with the left thyroid lobe absent. Compensatory hypertrophy occurs in most thyroid remnants. Associated diagnoses in the remaining lobe include hyperthyroidism, hypothyroidism, simple and multinodular goiter, and carcinoma. There is no increased risk for the subsequent development of cancer in the remaining lobe, and empiric thyroidectomy is not justified.ConclusionsThyroid hemiagenesis is an uncommon presentation that is frequently asymptomatic and detected incidentally when imaging for another condition. Awareness of its existence can help prevent unnecessary interventions associated with incorrect assumptions in patient care.