Usefulness of technetium-99m-meth-oxyisobutylisonitrile imaging and intraoperative staining technique using methylene blue for localization: Two cases of hyperfunctioning parathyroid lesions.

Abstract

Two patients with primary hyperparathyroidism in whom it was difficult to search the location of abnormal parathyroid tissues are presented. Both patients, 35-year-old woman and 49-year-old man, had experienced several episodes of urolithiasis. A right lower (the former case) or right upper (the latter) parathyroid tumor was suspected by ultrasonography, but ²⁰¹Tl-Cl and ^99mTc-pertechnetate subtraction scintigraphy (TTSS) demonstrated no abnormal accumulation in the thyroid bed or mediastinum. At operation, no abnormal parathyroid gland was found in both patients. ^99mTc-methoxyisobutylisonitrile scintigraphy revealed the presence of elusive parathyroid lesion in the mediastinum or at the lower position of the left thyroid lobe. At reoperation, intraoperative staining with methylene blue was useful to find out the lesions in both patients. The histological diagnosis was hyperplasia of the parathyroid in both. The normal calcium level was obtained promptly after the removal of these tissues.