Location of Parathyroid Adenomas: 7-Year Experience

Objective: To determine the most common location of parathyroid adenomas. Methods: Data from 147 patients who underwent parathyroidectomy for primary hyperparathyroidism in Montreal at a McGill University teaching hospital between January 2001 and January 2008 were reviewed retrospectively. Patients with histopathologic confirmation of parathyroid hyperplasia were excluded from the study (n = 26). The 121 patients with confirmed adenomas were grouped according to the locations of the tumour into right superior, right inferior, left superior, left inferior, and ectopic. Results: The left inferior parathyroid glands were the most common site of adenomas. This was the case for 50 patients (41.32% [mean 0.41; 95% CI 0.324-0.506]). The right inferior parathyroid glands were the site in 40 patients (33.06% [mean 0.33; 95% CI 0.248-0.422]). The remainder of the adenomas were distributed as follows: the left superior in 19 patients (15.7% [mean 0.157; 95% CI 0.097-0.234]), the right superior in 10 patients (8.26% [mean 0.0826; 95% CI 0.040-0.147]), and the ectopic in 2 patients (1.65% [mean 0.0165; 95% CI 0.002-0.058]). Conclusions: In this study, the most common site of adenoma was the left inferior parathyroid gland. This information provides parathyroid surgeons with a starting point when imaging fails to localize the site of the adenoma, which allows for the possibility of minimally invasive surgery especially if used in conjunction with intraoperative parathyroid hormone.