Clinical diagnosis and treatment of nonfunctioning pheochromocytomas in 14 patients.

OBJECTIVE: To analyze the clinical characteristics of nonfunctioning pheochromocytoma, and to evaluate the efficacy of 131I-metaiodobenzylguanidine (MIBG) scan in the diagnosis and perioperative treatment of nonfunctioning pheochromocytoma.

METHODS: The clinical data of 14 patients with nonfunctioning pheochromocytoma were analyzed retrospectively. Plasma free corticoid, renin, aldosterone, and urine catecholamines levels were estimated. B-mode ultrasonography, computed tomography scan, thoracic X-ray and 131I-MIBG were used.

RESULTS: All patients with nonfunctioning pheochromocytoma had no hypertension and the tumors were found incidentally. The 24 hours urine catecholamines levels in 80% (8/10) patients were normal. The positive rate of 131-MIBG was 80% (8/10) and the specificity was 100%. All patients underwent surgical operation of tumor resection. No preoperative volume expansion was given to all patients. All tumors were resected completely, and no death accident happened. There was no recurrence and metastasis after operation by long-term follow-up.

CONCLUSION: 131I-MIBG scan is the first choice technique for the diagnosis of nonfunctioning pheochromocytoma. Blood volume expansion is unnecessary before resection of pheochromocytoma.