Bilateral exploration in primary hyperparathyroidism: Double adenoma distribution and biochemical patterns over two decades.

Background: We investigated if anatomic patterns of abnormal parathyroid glands have ch anged for primary hyperparathyroidism (pHPT) as atypical biochemical presentation (normohormonal and normocalcemic) has increased.

Methods: Retrospective review of patients with pHPT who underwent routine bilateral neck exploration.

Results: 2762 patients were included. The "late" cohort (2014-2020) exhibited lower preoperative calcium (10.8 vs 11.1 ​mg/dL; P ​= ​0.001) and PTH levels (101 vs. 146 ​pg/mL; P ​= ​0.001) compared to the "early" cohort (2000-2006). Patients with atypical biochemical profiles increased from 25.5% to 31.3% (P ​< ​0.001). The prevalence of single adenoma (SA) decreased (66.1% vs 58.9%, P ​= ​0.02) while the proportion of double adenoma (DA) increased (17.3% vs. 22.6%, P ​< ​0.01). Upper parathyroid adenoma(s) remained the most common finding for SA and DA in both time points.

Conclusions: Despite changes in patient characteristics, single upper adenoma and bilateral double upper adenomas remain the most common findings for patients with pHPT.