Characteristics of Patients with Primary Hyperparathyroidism with Localization Failure of the Causative Parathyroid Gland: A Clinical Report and Literature Review.

Objective It is important to identify the causative parathyroid gland before parathyroidectomy in patients with primary hyperparathyroidism; however, there are some cases of preoperative localization failure. This study assessed the characteristics of patients with failure to localize the causative parathyroid gland. Methods This study included 114 patients with primary hyperparathyroidism. Physical and biochemical indices were measured, and neck ultrasonography, technetium-99m methoxy isobutyl isonitrile scintigraphy, and magnetic resonance imaging were performed. Localization of the causative gland was confirmed by consensus among multiple physicians. Results The causative parathyroid glands were localized in 83 patients (73%) with primary hyperparathyroidism. Successful localization was defined as cases in which preoperative imaging accurately identified the causative parathyroid gland, and localization failure included cases with no preoperative identification or those requiring additional resections due to incorrect localization. Most preoperative localization diagnoses in the patients who underwent parathyroidectomy were confirmed to be accurate. Patients with localization failure were significantly older and exhibited lower levels of serum chloride, calcium, intact parathyroid hormone, and urinary calcium values, along with higher serum phosphorus levels, greater phosphate reabsorption, and a smaller tumor size than those with successful localization. Even after adjusting for the age, sex, and body mass index, intact parathyroid hormone levels were significantly associated with successful localization. Conclusion A relatively old age; low levels of serum chloride, calcium, intact parathyroid hormone, and urinary calcium; high levels of serum phosphorus; phosphate reabsorption; and a relatively small tumor size were associated with localization failure of the causative parathyroid gland.