Predictors of parathyroid adenoma vs hyperplasia in primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disorder presenting with symptoms like osteoporosis, kidney stones or as asymptomatic hypercalcemia. The purpose of this study was to determine if there are clinical features that raise suspicion for parathyroid adenoma and hyperplasia. In time period 2005-2019 cohort of 412 patients with PHPT who underwent parathyroidectomy were reviewed. Patients (n=388) were divided into two groups according to morphology - 343 (83.3%) adenoma, 45 (10.9%) hyperplasia. From study 15 (3.6%) cancer and 9 (2.2%) patients with both morphologies (adenoma and hyperplasia) were excluded. Preoperative and postoperative calcium, symptoms - kidney stones and osteoporosis were analysed in patients with adenoma and hyperplasia. Median preoperative calcium in adenoma group was 2.80 mmol/l (2.24-4.36); hyperplasia group - 2.75 mmol/l (2.26-3.55). Median calcium drop after surgery in adenoma group was 0.53 mmol/l vs 0.51 mmol/l in hyperplasia group. Ninety-six (24.7%) of included PHPT patients had kidney stones, 164 (42.3%) osteoporosis, 48 (12.4%) both symptoms and 176 (45.4%) had no symptoms. No statistically significant difference was found between morphological groups regarding to kidney stones, osteoporosis or both. Calcium drop, kidney stones, osteoporosis are not reliable factors to distinguish between adenoma and hyperplasia preoperatively.