Endocrine Abstracts

Primary hyperparathyroidism (PHPT) is nowadays usually diagnosed as an asymptomatic disease but it might be related with advanced end-organ damage. Parathyroid incidentaloma (PI) is the term describing enlarged parathyroid nodules that are unexpectedly discovered on surgery or by imaging performed for nonparathyroid disorders. The recognition of PI might uncover a clinically significant PHPT with the potential for surgical cure. We retrospectively reviewed patients’ records with a newly diagnosed PHPT in the last 5 years in our hospital. Among 74 retrieved patients we found 14 (18.9%) diagnosed with PHPT following the discovery of PI. Nonparametric statistical tests were used for the comparison between this PI PHPT group and the rest of our cohort. Overall thirteen PHPT patients with PIs were discovered on neck ultrasound. The median volume of these PIs was 403.2 mm³ (117–1570 mm³). One PI was found during the surgery in a patient referred for thyroidectomy at our institution. The previous presence of PHPT in this case was suggested by development of transitory hypocalcemia due to hungry bone syndrome after the surgery. The rest of PHPT patients were mostly identified by incidental laboratory findings of hypercalcemia (36.5%) or during the osteoporosis work-up (32.4%). The comparison of the PI PHPT group with other PHPT patients found a statistically similar level of PTH, calciuria and eGFR. The highest serum calcium level measured before treatment was lower in PI PHPT patients (P = 0.037), but rates of normocalcemic PHPT were comparable in both groups. The PI PHPT group had more often positive scintigraphy (P = 0.027). Differences in the occurrence of osteoporosis and urolithiasis did not reach statistical significance. The PI PHPT group was less likely to meet the international consensus criteria for surgery (P < 0.01), but the frequency of surgical management did not differ between groups. The surgical cure for PHPT was achieved in all PI PHPT patients and pathohistology of all operated PIs confirmed adenomas. PIs are still an uncommon but relevant way of revealing PHPT. In our institution the radiological suspicion for enlarged parathyroid glands is further investigated only after the positive biochemical screening for parathyroid hyperfunction. This certainly introduces a bias in our clinical data because silent PIs are disregarded, similar to bias which exists in other circumstances of discovering asymptomatic PHPT. We emphasize that all relevant laboratory parameters are checked not to miss the normocalcemic PHPT. An appropriate follow up for suspicious silent nodules should be suggested.