Differences in single gland and multigland disease are seen in low biochemical profile primary hyperparathyroidism

Background. Primary hyperparathyroidism is characterized by increased levels of serum calcium and parathyroid hormone. Recently, 2 additional mild biochemical profiles have emerged, normocalcemic and normohormonal primary hyperparathyroidism. We reviewed our surgical experience of mild biochemical profile patients and compared them with classic primary hyperparathyroidism patients. Methods. This is a single institution, retrospective cohort review of all patients who underwent parathyroidectomy for primary hyperparathyroidism from 2006-2012. Preoperative and intraoperative variables were analyzed. Univariable analysis was performed with analysis of variance and the chi(2) test. A logistic regression was performed to identify significantly independent predictor variables for multigland disease. Results. A total of 573 patients underwent parathyroidectomy for primary hyperparathyroidism (classic, n = 405; normohormonal, n = 96; normocalcemic, n = 72). Normocalcemic primary hyperparathyroidism was associated with multigland disease in 43 (45 %, P <.001) patients as compared with the normohormonal (7, 10%) and classic (36, 9%) groups. On logistic regression, significant predictors for multigland disease were the normocalcemic subtype and positive family history. Twelve month biochemical normalization rates after operative treatment were > 98 % in all 3 groups. Conclusion. Our series shows that normocalcemic primary hyperparathyroidism is associated with a high incidence of multigland disease. Normohormonal disease is similar to classic disease patients with > 90% presenting with single adenomas. Excellent rates of biochemical normalization can be obtained by operative treatment in all 3 groups.