Undescended parathyroid adenoma: an important etiology for failed operations for primary hyperparathyroidism.

From July, 1982 to April, 1989, a total of 145 patients with persistent or recurrent primary hyperparathyroidism (HPT) were explored; 105 patients had an adenoma as the cause of HPT, and in 9 patients (9%), the abnormal gland was located at or superior to the carotid bifurcation (undescended parathyroid gland). These 9 patients had 14 prior explorations for HPT including 4 median sternotomies and 5 thyroidectomies. Each of the 9 patients was symptomatic of HPT, including bone disease in 8 of 9 patients and renal stones in 4 of 9 patients. Seven patients had an undescended parathyroid adenoma correctly localized preoperatively by ultrasound (n = 5), angiography (n = 5), venous sampling (n = 1), or computed tomography scan (n = 4). These 7 patients with accurate preoperative localization were explored by an incision anterior to the sternocleidomastoid muscle high in the neck that avoided the previous operative field and allowed rapid resection of the parathyroid adenoma. In the 2 patients who did not have accurate preoperative localization, the undescended adenoma was found after long tedious exploration including median sternotomy in 1 patient. Each patient (n = 9) who had an undescended parathyroid adenoma removed was cured of hypercalcemia, and 5 patients required postoperative 1,25-dihydroxy vitamin D3 for hypocalcemia. We conclude that undescended parathyroid adenomas comprise a significant proportion (9%) of adenomas during reoperations for persistent HPT.(ABSTRACT TRUNCATED AT 250 WORDS)