Preoperative localization of supernumerary and ectopic parathyroid glands in patients with secondary hyperparathyroidism

The undetectable supernumerary and ectopic parathyroid glands have a high risk of persistent and recurrent hyperparathyroidism, especially in the patients with secondary hyperparathyroidism. Preoperative image diagnosis, CT scan, echogram and 201T1C1 scintigram were very useful for detecting supernumerary and ectopic parathyroid glands in our 132 patients who underwent parathyroidectomy for secondary hyperparathyroidism. Among these methods the scintigraphy showed the highest detection rate of the glands in the thymic tongue and in the upper mediastinum. CT scan showed the best detection rate of the glands located in the thyroid gland and those located between the thyroid gland and trachea. The echography was useful in detecting the glands in the thyroid gland, but could not offer easy visualization those located in the mediastinum. Even the ectopic parathyroid glands, weighing more than 500 mg were identifiable at about 90% when all the methods were applied routinely. In our experience, four patients had a supernumerary gland which was detected by the preoperative image diagnostic procedures at the initial surgery. One patient had a supernumerary gland in the mediastinum which was detected by image diagnosis after the initial operation and was removed at reoperation.