Clinicopathological insights into primary hyperparathyroidism: a comprehensive single-center retrospective study

Primary hyperparathyroidism (PHPT) is caused by excessive hormone secretion from one or more parathyroid glands. Based on their morphological and immunophenotypic characteristics, parathyroid glands can be considered as neuroendocrine organs, and their neoplasms as neuroendocrine tumors. The 2022 World Health Organization (WHO) Classification of Endocrine and Neuroendocrine Tumors introduced updated diagnostic criteria, advancing the understanding of parathyroid neoplasms. This study aimed to analyze the clinicopathological features of PHPT, emphasizing tumor localization and histopathological findings.

The retrospective study analyzed 39 surgically treated patients for PHPT at a single tertiary referral center between 2022 and 2024. Localization methods included neck ultrasonography (US), technetium-99m methoxyisobutylisonitrile single photon emission computed tomography/computed tomography ([99mTc]Tc-MIBI SPECT/CT), and ¹⁸F-fluorocholine positron emission tomography/computed tomography (¹⁸F-FCH PET/CT). Postoperative histopathological evaluation of specimens was conducted according to the 2022 WHO criteria.

The cohort comprised 85% female patients with a mean age of 57.8 years. Lower parathyroid glands were more frequently affected, reflecting their distinct embryological origins. Pathological analysis identified 77.5% parathyroid adenomas (PA), 12.5% atypical parathyroid tumors (APT), and 7.5% parathyroid carcinomas (PC), with the incidence of APT and PC exceeding reported ranges. PET/CT showed superior diagnostic accuracy (100% detection) compared to neck US (65.8%) and [99mTc]Tc-MIBI SPECT/CT (65.7%). Maximum standardized uptake value (SUVmax) from PET/CT significantly correlated with serum calcium, PTH concentration, and lesion volume, suggesting their utility as markers of metabolic activity. Surgery achieved a 92.3% cure rate, with successful reoperations in all recurrent cases.

The study underscores the neuroendocrine nature of parathyroid glands, highlights the diagnostic value of the updated WHO classification, and demonstrates the superior accuracy of 18F-FCH PET/CT in localizing parathyroid lesions. A deeper understanding of the neuroendocrine characteristics of parathyroid glands and their embryological migration patterns could further improve diagnostic and therapeutic strategies. Early diagnosis and precise localization of affected parathyroid glands remain critical for achieving curative outcomes in PHPT.