Mediastinal parathyroid exploration: A clinical and pathologic study of 47 cases

Of the 1,200 patients with hyperparathyroidism surgically treated at the Massachusetts General Hospital (MGH) from 1926 to 1984, there were 47 who underwent mediastinal exploration. Of these, 30 patients (64%) had hyperfunctioning parathyroid glands successfully excised by median sternotomy. Twelve of these underwent their initial neck operation at the MGH, and 18 were referred to us having undergone 1 or more previous unsuccessful neck explorations. There were 17 females and 13 males. The ages of these patients ranged from 17 to 75 years. Twenty‐four patients had nephrolithiasis or nephrocalcinosis; 15, osteitis fibrosa cystica; 14, renal and bone disease; 6, peptic ulcer disease; 2, hypertension; and 1, gouty arthritis. Two patients were asymptomatic with hypercalcemia detected by routine simultaneous multichannel analyzer. The serum calcium level ranged from 11.4 to 18.4 mg/100 ml with a mean of 13.8 mg/100 ml, and phosphorus from 1.4 to 3.3 mg/100 ml with a mean of 2.0 mg/100 ml. Of the 11 patients who had plasma parathyroid hormone determinations, the values ranged from 1 to 11 times normal. In 24 patients, the mediastinal tumor was intrathymic in location and the remaining 6 were parathymic, either adjacent to the great vessels or the pleura. The tumors varied greatly in size, ranging from 0.7 to 5.0 cm in greatest dimension, weighing 0.3 to 18.0 g. Five of these patients had hyperfunctioning supernumerary glands. Pathologic evaluation revealed 26 parathyroid adenomas and 4 primary hyperplastic glands. In 17 patients (36%) mediastinal exploration was unsuccessful. Four of the patients successfully explored developed permanent hypocalcemia. The complications included 1 recurrent laryngeal nerve injury, 1 phrenic nerve injury, 1 pneumothorax, and 1 spontaneously resolving postoperative pleural effusion. There were no deaths or other significant complications. We believe hyperfunctioning mediastinal tumors are rare and mediastinal exploration should be undertaken only when careful selective criteria are met.