Thyroid Scintigraphy of a Rare Case of Left Thyroid Lobe Hemiagenesis With Subacute Thyroiditis.

Thyroid hemiagenesis is a rare developmental anomaly. Patients with thyroid hemiagenesis have higher incidence of coexisting thyroid disorders in the remaining lobe. We present a rare case of a 21-year-old woman with subclinical hyperthyroidism incidentally found to have thyroid hemiagenesis on thyroid 123I-Na scan, which is confirmed on thyroid ultrasound.