Decrement in bone mineral density after parathyroidectomy in a pediatric patient with primary hyperparathyroidism

Abstract

Primary hyperparathyroidism (PHT) causes increased bone turnover, leading to reduction in bone mineral density (BMD). Parathyroidectomy is a definitive therapy and improves BMD in adult patients with PHT. However, there are no reports regarding alterations of BMD in pediatric or adolescent patients with PHT. Here, we report a case of a 13-yr-old boy with PHT who was referred to our institution for evaluation of hypercalcemia and hyperparathyroidism. Radiological investigation revealed an ectopic parathyroid adenoma below the right thyroid lobe. A minimally invasive radio-guided parathyroidectomy was successfully performed. We followed up the patient's BMD for three years both before and after parathyroidectomy. Over the course of three years, his BMD was steadily decreased, with z-scores of +0.506 at 13 yr and 9 mo, +0.162 at 14 yr and 9 mo, and -0.411 at 15 yr and 9 mo. BMD usually increases during peak height velocity in an adolescent and improves after parathyroidectomy in adult patients with PHT. However, our patient showed decreased BMD z-scores following parathyroidectomy. Therefore, the patient had an increased risk of fracture after parathyroidectomy and was followed up closely. Both height and BMD should be carefully evaluated after parathyroidectomy in pediatric and adolescent patients with PHT.

Keywords: bone mineral density; ectopic parathyroid gland; hyperparathyroidism; short stature.

Fig. 1.

Growth chart (representative of Japanese boys aged 0–18 yr). The patient’s growth curve was just below the −2 SD line before the onset of PHT. Although pubertal development started normally, his growth spurt ceased early. The black and gray arrows show the time of disease onset and surgery, respectively.

Fig. 2.

Radiological findings. Contrast-enhanced computed tomography (CT) (A), technetium-99m sestamibi (B), single photon emission CT (C), and three-dimensional CT (D) scans demonstrate an ectopic parathyroid adenoma below the right thyroid lobe.