An approach to a patient with primary hyperparathyroidism and a suspected ectopic parathyroid adenoma.

Abstract

Primary hyperparathyroidism (PHPT) is characterised by hypercalcemia driven by excess parathyroid hormone (PTH) secretion. PHPT is a common endocrine condition with a prevalence of one to seven cases per 1000 adults. PHPT typically presents in the fifth or sixth decade and shows significant female preponderance. Solitary hyper-functioning parathyroid adenomas account for 85-90% of PHPT cases. The remaining 10-15% include cases of multi-glandular disease (multiple adenomas or hyperplasia) and, rarely, parathyroid carcinoma (1%). Ectopic parathyroid adenomas may arise due to abnormal embryological migration of the parathyroid glands and can be difficult to localise pre-operatively, making surgical cure challenging on the first attempt. The potential existence of multiglandular disease should be considered in all patients in whom pre-operative localization fails to identify a target adenoma, or following unsuccessful parathyroidectomy. Risk factors for multiglandular disease include underlying genetic syndromes (e.g., MEN1/2A), lithium therapy, or previous radiotherapy. In addition to multifocal disease, the possibility of an ectopic parathyroid gland should also be considered in patients requiring repeat parathyroid surgery. In this article, we use illustrative clinical vignettes to discuss the approach to a patient with PHPT and a suspected ectopic parathyroid adenoma.