Approach to the Patient with Primary Hyperparathyroidism in Multiple Endocrine Neoplasia Type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary disorder in which patients develop multiple endocrine tumors simultaneously. Among these, primary hyperparathyroidism (PHPT) is the most common and often the earliest manifestation. All patients with MEN1 and hypercalcemia should have surgery, with most patients requiring surgical treatment before the age of 50. The timing of parathyroid surgery mainly depends on hypercalcemia and the presence of renal or skeletal complications. The goals of treatment are to correct hypercalcemia, prevent target organ damage, and minimize the risk of postoperative hypoparathyroidism as much as possible. Currently, the most widely recommended surgical approach is subtotal parathyroidectomy via cervical approach (removal of 3 or 3.5 glands). With advances in imaging technology, patients with clearly localized lesions—particularly younger patients—may be candidates for individualized unilateral resection (i.e., removal of both glands on the affected side). In addition, recurrent hypercalcemia after surgery is relatively common in MEN1 patients. The management of the remaining glands remains challenging, such patients usually need reoperation, calcimimetic therapy or clinical observation. For patients requiring repeated parathyroid surgeries, in addition to searching for multifocal lesions, the possibility of ectopic parathyroid glands should also be taken into account. Ectopic parathyroid adenoma, caused by abnormal embryonic migration, complicates surgery in both sporadic and MEN1-related PHPT. However, in MEN1, their higher frequency and multiglandular distribution make localization even more challenging, often leading to incomplete resection and recurrence.