Is Thyroid Hemiagenesis Really Seen Seldomly?: Two Case Reports and Review of the Literature - Case Report

Abstract

Thyroid hemiagenesis is a rare embriological anomaly. It is diagnosed incidentally during examination for other thyroid gland diseases. Two patients with hemiagenesis of the thyroid gland were presented. 
Case Reports: The first patient was a 36-year-old woman with thyroid hemiagenesis presented with euthyroidism. Thyroid peroxide antibody and thyroglobulin levels were normal. Tc-99m pertechnetate scan and ultrasonography (US) findings demonstrated absence of the left lobe of the thyroid gland. A fine needle aspiration biopsy of the right lobe showed benign follicular cells. The second patient, a 31-year-old woman presented with subclinical hypothyroidism. Thyroid peroxide antibody and thyroglobulin levels were very high. Tc-99m pertechnetate scan revealed absence of the right lobe and isthmus of the thyroid gland and minimal hyperplasic left lobe. Thyroid ultrasonography (US) demonstrated a normal sized, pseudonodular left lobe of the thyroid gland with no visualization of the right lobe and isthmus. A fine needle aspiration biopsy of the left lobe showed lymhocytes. 
Conclusion: There are more than 270 thyroid hemiagenesis cases reported in the literature. But this may not reflect the true incidence of thyroid hemiagenesis.