Variation in parathyroid adenoma size in patients with sporadic, primary hyperparathyroidism: small gland size does not preclude single gland disease.

Abstract

Small, abnormal parathyroid glands are usually associated with multigland hyperplasia in patients with primary hyperparathyroidism (pHPT). The purpose of this study was to determine the association between parathyroid adenoma size and biochemical cure rates in patients undergoing single gland parathyroidectomy. The study included patients with sporadic pHPT who underwent initial parathyroidectomy and met intraoperative PTH criteria for cure after resection of a single adenoma (SGD). Patients were divided into quartiles (Q1 = smallest) based on gland weight and maximum dimension; cure rates were compared across groups. A single parathyroid adenoma was removed in 517 patients, with a median gland weight of 500 mg (range 50-11890). Median maximum gland dimension was 15 mm (range 5-55). With median follow-up of 28 months (range 6-81), the biochemical cure rate was 97.1%. There was no difference in cure rate by gland weight (Q1 94.6%, Q2 96.9%, Q3 98.4%, Q4 98.5%, p = 0.217) or maximum gland dimension (Q1 95.6%, Q2 97.6%, Q3 97.1%, Q4 98.2%, p = 0.641). When Q1 patients (by gland weight) were divided by quartile, there was no difference in cure rates (93.1% [50-140 mg]; 95.2% [150-190 mg]; 97.1% [200-230 mg]; 93.3% [240-280 mg]; p = 0.665). For patients with pHPT who underwent single gland parathyroidectomy, there was no difference in cure rates by gland weight or maximum dimension. These data suggest that the removal of parathyroid adenomas as small as 50 mg with an appropriate decline in ioPTH likely represent single gland disease and additional exploration may not be necessary.