Location of parathyroid adenomas: 7-year experience

To determine the most common location of parathyroid adenomas.

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.

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]).

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.