Ectopic and supernumerary parathyroid glands in patients with refractory renal hyperparathyroidism

The aims of this study were to determine the rate of ectopic and supernumerary parathyroid glands and the outcome of surgical therapy in patients with refractory renal hyperparathyroidism.

A retrospective review of all patients who underwent parathyroidectomy for refractory renal hyperparathyroidism was completed. Operative and pathology reports were reviewed, and the number and location of resected parathyroid glands, patient outcomes, and follow-up were determined.

During the period 1993-2019, a total of 68 patients underwent subtotal or total parathyroidectomy for renal hyperparathyroidism. Of those, 59 patients (87%) were on dialysis for an average of 6.7 years. We determined that 18 patients (26%) had 24 ectopic parathyroid glands, including 9 (13%) patients with 11 supernumerary glands. A total of 2 patients had a supernumerary gland in a normal anatomic location. Of the 24 ectopic glands, 14 (58%) were in the thymus. After parathyroidectomy, 4 patients (5.9%) had persistent hyperparathyroidism, 6 patients (8.8%) developed recurrent hyperparathyroidism, and 2 patients (3%) had permanent hypoparathyroidism.

Ectopic and supernumerary parathyroid glands occurred in 26% and 16% of patients with renal hyperparathyroidism, respectively, and the thymus was the most common location. Thorough neck exploration and transcervical thymectomy are important to help reduce persistent and recurrent hyperparathyroidism after parathyroidectomy for renal hyperparathyroidism.