Intrathyroidal parathyroid glands can be a cause of failed cervical exploration for hyperparathyroidism

The incidence of intrathyroidal parathyroid glands remains controversial. The purpose of this study was to determine the incidence in a series of patients with hyperparathyroidism. Three hundred nine patients underwent parathyroidectomy. Patients were divided into two groups: uniglandular disease versus hyperplasia. Eighteen of 309 patients (6%) had abnormal intrathyroidal parathyroid glands. The incidence was 3% (7 of 222) in patients with uniglandular disease versus 15% (11 of 73) in those with hyperplasia. With a mean follow-up of 54 months, 12 patients are eucalcemic, 5 have persistent hypocalcemia, and 1 has recurrent hypercalcemia. There were no recurrent laryngeal nerve injuries. These data suggest that an intrathyroidal adenoma is an uncommon cause of failure, whereas abnormal intrathyroidal parathyroid tissue may be a more common cause of failure in patients with hyperplasia.