Incidence and location of ectopic abnormal parathyroid glands

Background Ectopic parathyroid glands are a cause for failed parathyroid exploration. Methods Patients with hyperparathyroidism and ectopic parathyroid glands were identified from a parathyroid database. Laboratory data, gland weights, and surgical outcomes were obtained. The locations of the ectopic glands were correlated with results of technetium-99m–sestamibi imaging. Results Of 231 patients operated on for hyperparathyroidism, 37 (16%) had ectopic parathyroid glands. Ectopic inferior glands (N = 23 [62%]) were intrathymic, n = 7 (30%); anterosuperior mediastinal, n = 5 (22%); intrathyroidal, n = 5 (22%); within the thyrothymic ligament, n = 4 (17%); and submandibular, n = 2 (9%). Ectopic superior glands (N = 14 [38%]) were in the tracheoesophageal groove, n = 6 (43%); retroesophageal, n = 3 (22%); posterosuperior mediastinal, n = 2 (14%); intrathyroidal, n = 1 (7%); in the carotid sheath, n = 1 (7%); and paraesophageal, n = 1 (7%). Sestamibi scans were true-positive in 81%, identifying 13 of 16 retrosternal glands, and false-negative in 19%. Conclusions A 16% incidence of ectopic parathyroid glands and a 100% positive predictive value of sestamibi scintigraphy underscore the importance of sestamibi imaging in patients with primary hyperparathyroidism.