Increased sensitivity and accuracy of phaeochromocytoma diagnosis achieved by use of plasma-adrenaline estimations and a pentolinium-suppression test.

26 patients with suspected phaeochromocytoma underwent selective venous sampling: a tumour was identified and removed in 18.4 of these patients did not have sustained hypertension, and the only persistent abnormality was an elevated plasma-adrenaline level. The increased plasma-catecholamine concentrations in the tumour patients were not suppressed by pentolinium 2.5 mg i.v., whereas the levels in the 8 non-tumour patients were lowered to the normal range. Calculations based on the arteriovenous differences of adrenaline and noradrenaline suggest that adrenal medullary secretion contributed less than 2% of circulating noradrenaline in the non-tumour patients. Plasma-adrenaline, however, is derived almost entirely from the adrenal gland, and its estimation appears superior to that of noradrenaline in the detection of a small adrenal phaeochromocytoma.