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.