[Localization of pheochromocytomas by 131-I-meta-iodobenzylguanidine scintigraphy]

Scintigraphy using 131I-labeled meta-iodobenzylguanidine was performed in 89 patients. A diagnosis of pheochromocytoma was indicated by urinalysis in 28 cases and confirmed histologically in the 27 patients who underwent surgery. The tumor was located using scintigraphy and computed tomography. Fourteen isolated and 6 malignant metastatic pheochromocytomas were found as well as 8 pheochromocytomas associated with genetic disease. Scintigraphy located the tumors in 22 out of 28 cases; however, 3 adrenal pheochromocytomas and 3 malignant pheochromocytomas were not detected. Radioisotope perfusion scanning was more sensitive than computed tomography for the detection of bilateral adrenal pheochromocytoma. In the only case of a multifocal tumor, a combination of scintigraphy and computed tomography located all pheochromocytomas which were later resected. The high number of patients without elevated urine catecholamines and in whom scintigraphy did not alter the diagnosis shows that his technique should be applied only after demonstration of catecholamine hypersection.