Bone and Mineral Metabolism Phenotypes in MEN1-Related and Sporadic Primary Hyperparathyroidism, before and after Parathyroidectomy

Primary hyperparathyroidism (PHPT) is the most common endocrinopathy in multiple endocrine neoplasia type 1 (MEN1). Persistent levels of increased parathyroid hormone (PTH) result in a higher incidence of osteopenia and osteoporosis compared to the general population. Surgical removal of hyper-functioning parathyroid tissue is the therapy of choice. This retrospective study evaluated the effect of parathyroidectomy (PTX) on bone metabolism and bone mass in two series of patients with MEN1 PHPT and sporadic PHPT (sPHPT) by comparing bone metabolism-related biochemical markers and bone mineral density (BMD) before and after surgery. Our data confirmed, in a higher number of cases than in previously published studies, the efficacy of PTX, not only to rapidly restore normal levels of PTH and calcium, but also to normalize biochemical parameters of bone resorption and bone formation, and to improve spine and femur bone mass, in both MEN1 PHPT and sPHPT. Evaluation of single-patient BMD changes after surgery indicates an individual variable bone mass improvement in a great majority of MEN1 PHPT patients. In MEN1 patients, PTX is strongly suggested in the presence of increased PTH and hypercalcemia to prevent/reduce the early-onset bone mass loss and grant, in young patients, the achievement of the bone mass peak; routine monitoring of bone metabolism and bone mass should start from adolescence. Therapy with anti-fracture drugs is indicated in MEN1 patients with BMD lower than the age-matched normal values.