PRIMARY HYPERPARATHYROIDISM DETECTED BY PARATHYROID INCIDENTALOMA: CLINICAL FEATURES, WORK-UP AND MANAGEMENT.

Context: With the widespread use of neck ultrasound, parathyroid incidentaloma (PI) emerges as an additional opportunity for incidental detection of primary hyperparathyroidism (PHPT).

Objective And Design: This study aimed to investigate PHPT cases detected by PI and to compare them with other PHPT patients. A retrospective analysis of newly diagnosed PHPT patients between 2014 and 2020 was conducted in our hospital.

Subjects And Methods: The cohort of 124 subjects was divided in two groups: 22 (17.7%) PHPT patients detected by PI (PI PHPT group) and the rest of 102 PHPT patients (non-PI PHPT group). Overall, 21 PIs were discovered on ultrasound and one was found during thyroid surgery. Clinical features, work-up and management of two study groups were compared.

Results: The PI PHPT group had lower ionized calcium at diagnosis (p=0.034), lower peak serum calcium during follow-up (p<0.01), less fractures (p=0.022) and was less likely to meet the international criteria for parathyroidectomy (p<0.01). Positive sestamibi scan (p=0.022) and confirmed concordant localization in at least two different parathyroid imaging techniques (p=0.033) were more likely in the PI PHPT group. The frequency of surgical management did not differ between groups.

Conclusions: PHPT detected by PI is clinically relevant and mostly comparable to PHPT in other patients with some features that correspond more often to a mild disease. Higher rate of positive preoperative localization in PHPT detected by PI might encourage parathyroidectomy even without the international criteria met.