PHEOCHROMOCYTOMA

also called Chromaffinoma, tumour, most often nonmalignant, that causes abnormally high blood pressure because of hypersecretion of the hormones epinephrine and norepinephrine. Usually the tumour is in the medullary cells of the adrenal gland but may occur elsewhere; e.g., in the chromaffin tissues of the ganglia of the nervous system. The hypertension may be persistent or paroxysmal (periodic). Patients with persistent hypertension usually are afflicted with a constant headache, are thin and nervous, and have high blood sugar and an elevated basal metabolic rate. In paroxysmal attacks of hypertension, which last from one-half to three-quarters of an hour, the headache is much more intense and is accompanied by sweating, pallor, and tremor. Surgical removal of the tumour is the most effective treatment of the disorder. Pheochromocytoma is an uncommon cause of hypertension, perhaps causing only one out of every 1,000 cases of that disorder.