False positive metaiodobenzylguanidine scan in a patient with a huge adrenocortical carcinoma

We report a case of a 17-cm cortisol-secreting adrenocortical carcinoma in which [I-123]metaiodobenzylguanidine (MIBG) scan showed accumulation of the isotope in the area of the tumor. Catecholamine levels were normal, and no chromaffin cells were found in histological examination of the tumor. A li terature review of previously described conclude that MIBG scans might not be as specific as previously thought in differentiating pheochromocytoma fr om adrenocortical carcinoma. They should be performed only when clinical su spicion and abnormalities in catecholamines advocate the need.