Graves Disease With Midline Ectopic and Bifid Pyramidal Lobes on Pertechnetate Thyroid Scintigraphy

Abstract

Thyroid ectopia may present in isolation as the only functioning gland or may coexist along with a normal pretracheal thyroid. It is usually an asymptomatic mass and tends to increase in size under stress, when hormone demands increase, as in puberty, pregnancy, and stress. A pyramidal lobe is visualized when there is significant stimulation to the thyroid, is usually unilateral, and can arise from either lobe or isthmus, extending superiorly. We present a case of a patient with Graves disease, demonstrating an ectopic midline inferior nodule and bilateral pyramidal lobes on a pertechnetate thyroid scan. A 31-year-old male patient presented with a recent history of progressively increasing tremors, weight loss, tiredness, and increased sweating of 5-months duration. He had no history of thyroid complaints or contributory medical, surgical, and family history. On general physical examination, he had tachycardia with a pulse rate of 108/minute, fine tremors of the extremities, mild thyromegaly, and increased palmar sweating. His thyroid function tests were T3: 7.8 ng/mL (normal range 0.8–1.8 ng/mL), T4: 24.9 μg/dL (normal range 4.5–12.5 μg/dL), and TSH: 002 μIU/mL (normal range 0.5–9 μIU/mL). Tc 99m pertechnetate imaging was performed, which demonstrated diffuse, homogenous increased tracer uptake in bilateral thyroid lobes, bifid pyramidal lobes, and suppressed salivary gland uptake. In addition, there was a midline focus of intense tracer uptake inferior and separate from the thyroid margin, demonstrating increased vascularity on the flow images. USG Doppler was performed, which demonstrated increased vascularity in the nodule, supplied by the inferior thyroid artery and the echo texture similar to the rest of the thyroid tissue. Repeat pertechnetate scan done 3 months later demonstrated similar scan findings with a mild increase in the thyroid uptake (23%-33%). He was treated with 10 mCi of I-131 and is presently on follow-up and is asymptomatic.