Parathyroid localization: inability to predict multiple gland involvement.

Preoperative localization using various imaging techniques can accurately predict the location of solitary parathyroid adenomas in about 75% of patients. Its value has been questioned because of the high success rate of parathyroid exploration without localization. The ability of localization studies to differentiate preoperatively between patients with solitary adenomas and those with multiple gland disease would be valuable because bilateral exploration might be avoided in many cases. Ultrasonography, thallium-201/technetium-99m subtraction scintigraphy, and magnetic resonance imaging were used to evaluate 16 patients with primary hyperparathyroidism who were ultimately found at surgery to have multiple enlarged parathyroid glands. No single imaging technique was able to identify more than 53% of enlarged glands, and only four patients were accurately predicted preoperatively to have enlargement of multiple parathyroid glands. Existing imaging techniques cannot be relied on to predict multiple gland involvement preoperatively. Bilateral surgical exploration is mandatory in all patients with primary hyperparathyroidism.