[Topographic diagnosis of pheochromocytoma. Value of computerized axial tomography]

The localisation of a pheochromocytoma is difficult and sometimes hazardous. There are many radiological techniques of varying sensitivity and the risks of hypertensive crises or of cardiovascular collapse are not negligeable (especially during arteriography and venography). Abdominal computerised axial tomography (CAT) would appear to be of considerable value. It gives a very precise localisation without any risk. Three personal cases confirm this opinion. The first case was of a 38 year old man with an extra-adrenal pheochromocytoma localised in the pelvis of the left kidney by CAT (after negative intravenous urography); the second case was of a 54 year old man with a left adrenal pheochromocytoma confirmed on CAT (after 2 negative aortic arteriogrammes and adrenal venography); the third case was of a 39 year old woman with a para aortic pheochromocytoma, diagnosed on CAT (after negative intravenous urography). These three cases bring to 43 the total number of reports of pheochromocytoma localised by abdominal CAT. When this method is compared with intravenous urography and aortic arteriography, abdominal CAT is over three times more sensitive than intravenous urography (90% compared to 26%) and also more sensitive than arteriography (90% compared to 76%). The false negative results on CAT usually involve small tumours (diameter less than 30 mm). The new generation of CAT should reduce these errors. The great advantage of this investigation should change the order of the radiological examinations in the localisation of pheochromocytoma. It would seem logical to carry out an abdominal CAT as soon as biological confirmation of the hypersecretion of catecholamines had been obtained. The other radiological investigations (especially aortic arteriography) should be reserved for cases with negative abdominal CAT.