Endocrine Abstracts

Introduction: Primary hyperparathyroidism (pHPT) is the most common cause of hypercalcemia in the outpatient setting and is a frequent endocrine disorder. Large cohort studies of pHPT patients in the Portuguese population are scarce.

Aim: To characterize patients with pHPT followed at a tertiary center.

Material and Methods: Retrospective analysis of clinical records of patients with pHPT followed in our hospital from 2003 to 2021.

Results: A total of 177 patients were included, 82.5% were female. The mean age was 61±13.6 years. In 79.6% of the cases, hypercalcemia was detected in a routine analysis. Some patients had complaints of muscle and/or bone pain (33.3%), asthenia (27.6%) and polydipsia and polyuria (15.5%). 124 (80%) patients had DXA scan done out of which 37.4% had osteoporosis and 28.5% had osteopenia. History of fragility fractures was seen in 9.4% of the patients; nephrolithiasis was present in 37.5%; hypercalciuria (>400 mg/24h) in 17.1% and renal function impairment in 7.0%. At diagnosis, the mean ionized calcium, total calcium, phosphate, parathormone and 25-OH D levels were 1.44±0.17 mmol/l; 11.52±1.20 mg/dl; 2.71±0,62 mmol/l; 333.90±891.80 pg/ml and 20.61±10.ng/dl, respectively. 14 (7.9%) patients presented normocalcemic pHPT. Neck ultrasound and sestamibi scan detected parathyroid disease in 53.7% and 81.5% of the cases. 111 patients (62.7%) underwent surgical treatment, only two patients with pHPT normocalcemic. Pathological examination revealed a parathyroid adenoma (PT) in 65.5%, atypical adenoma 5.4%, hyperplasia 14.5%, carcinoma 9.0% and no parathyroid tissue in 6.3% of the patients. Right inferior parathyroid gland was the most common site of PT. A >50% decline of PTH 10-15 minutes after gland excision was observed in 80.8% of the patients. Post-operative transient and permanent hypocalcemia was observed in 52.4% and 8.5% of the cases. After PT surgery, the cure rate was 84.8%. Persistence and recurrence disease rates were 9.9% and 3.6% respectively. Hereditary forms of hyperparathyroidism were present in 11 patients: MEN-1 in 4 (2.3%) patients and MEN2A in 7 (4.0%). Somatic CDC73 mutations were found in 3 patients with PT carcinoma.

Conclusion: To the best of our knowledge this is the largest cohort of patients with pHPT in Portugal. Despite the diagnosis being mostly incidental with most patients presenting mild hypercalcemia, some were found to have evidence of skeletal and renal manifestations of the disease.