Pitfalls in the diagnosis of extraadrenal pheochromocytoma.

Precise localization of pheochromocytomas is an essential part of their preoperative management. As a significant number of these tumors may be extraadrenal multiple, or hypovascular, they may not be detected by computerized body tomography (CBT) or arteriography without film subtraction. In seven patients with extraadrenal pheochromocytomas, all tumors were demonstrated by arteriography. In two cases, subtraction films revealed tumors that had not been visualized on the non-subtraction films. CBT, performed in four patients, demonstrated a mass in two but failed to visualized tumors in the other two.