Technetium-99m pertechnetate uptake in ectopic parathyroid adenoma

Abstract

A 37-year-old male with a persistent increased parathyroid hormone level, after subtotal thyroidectomy and parathyroidectomy, was referred for scintigraphic localization of a possible ectopic parathyroid adenoma. Tc-99m pertechnetate and Tc-99m MIBI scintigraphy were performed on separate days. There was marked uptake of both tracers in the mediastinum, which at surgery was confirmed to be an extrathyroidal parathyroid adenoma. Hypervascularity was suggested as a possible explanation for rare cases of pertechnetate avid parathyroid adenomas. And Tc-99m MIBI scintigraphy proved to be a successful imaging procedure for ectopic parathyroid tissue.

Unexpected Appearance of Ectopic Mediastinal Toxic Nodulary Thyroid Hyperplasia in a Case of Recurrent Hyperthyroidism

“…On thyroid scintigraphy, mediastinal mass which showed no continuity with the overlying thyroid, was Tc-99m pertechnetate avid. However mediastinal pathologies other than ectopic thyroid tissue have been previously reported to be positive on thyroid scan [8,11,12]. So we performed other confirmatory examinations before surgery.…”

Comment on A. Ghemigian, et al Familial isolated primary hyperparathyroidism due to HRPT2 mutation

“…[4][5][6][7] The mechanism of 99m Tc-pertechnetate localization in the parathyroid remains uncertain. Hypervascularity is the most cited explanation since there is no known cellular mechanism by which parathyroid tissue could actively trap technetium, which is an iodine analogue.…”

“…Hypervascularity is the most cited explanation since there is no known cellular mechanism by which parathyroid tissue could actively trap technetium, which is an iodine analogue. 6,7 Other possibilities that have been proposed are the presence of a fibrous capsule around the tumor and intratumoral hemorrhage. …”