Evidence for extratumoural storage of catecholamines in pheochromocytoma patients

Following the removal of a pheochromocytoma in three female patients the daily excretion of catecholamines and their metabolites was still considerably elevated for about one week. The excretion rates declined during this period with half-lives of 1.8 to 10.9 days for catecholamines and 2.1 to 4.7 days for metanephrines, vanilmandelic acid, and vanilglycol. The cumulative urinary excretion of catecholamines and their metabolites following surgical removal of the tumour was nearly as high as the catecholamine content of the pheochromocytomas. This large amount of catecholamines must have been located outside the tumour, most probably within the sympathetic nerve, where it is subject to release following physiological stimuli. Furthermore, this fact may provide an explanation for hypertensive crises in pheochromocytoma patients.