Hyperthyroidism Incidentally Noted on Lymphoscintigraphy

Abstract

A 43-year-old woman with edema in both left upper limb and lower limb underwent lymphoscintigraphy to evaluate possible lymphedema. Two separate lymphoscintigraphies, one for the lower and the other for the upper limbs, were performed with interval of 3 days. Incidentally, an activity in the region of the thyroid glands was noted in the delayed images of both studies. Subsequently, Graves disease was diagnosed based on the patient’s symptoms and the results of laboratory examinations.

Thyroid Accumulation of 99mTc-DTPA in Graves Disease

“…Incidentally, the thyroid gland was clearly visualized ( B ), mimicking 99m Tc-pertechnetate uptake. Thyroid visualization due to uptake of unlabeled free 99m TcO 4 − has been recognized in previous nuclear medicine studies in patients with hyperthyroidism, such as 99m Tc-MAA pulmonary perfusion scintigraphy and 99m Tc-dextran lymphoscintigraphy 1,2 . Of discriminative value in the current study, the salivary glands ( B ), oral cavity ( B ), and stomach ( A ) were not simultaneously visualized, and the radiochemical purity of the administered 99m Tc-DTPA was 99%.…”