Change in I-123 Uptake by a Hyperfunctioning Thyroid Nodule in a Patient With Multinodular Goiter and Subclinical Hyperthyroidism

Multinodular goiter is characterized by heterogeneous thyroid growth that results in one or more dominant nodules superimposed on many nonpalpable ones. Over time, nodules display slow growth, stasis, or regression, and variable iodine uptake on nuclear imaging. Subclinical hyperthyroidism is characterized by suppressed TSH, normal free T3 and T4, and variable expression of signs and symptoms of hyperthyroidism. The case of a dominant hot nodule within a multinodular goiter representing a hyperplastic colloid nodule or nonautonomous hyperfunctioning (follicular) adenoma producing subclinical hyperthyroidism that subsequently became cold with normalization of TSH is presented.