[Detection, diagnosis and localization of pheochromocytoma. 77 cases in a population of 21,420 hypertensive patients].

Phaeochromocytoma was diagnosed in 77 (0.36%) of 21,420 hypertensive patients examined in the hypertension units of the Broussais and Saint-Joseph hospitals, Paris, between 1976 and 1986. Our diagnostic strategy is to reserve biochemical examinations to cases with suspected phaeochromocytoma and to explore only those patients who have positive laboratory results. Patients suspected of harbouring a phaeochromocytoma are those who complain of headaches, palpitations and sweating (these 3 symptoms together having a 90.9% sensitivity and a 99.9% exclusion value), those who have a family history of phaeochromocytoma or who present with medullary thyroid carcinoma or phakomatosis, or those who do not respond to anti-hypertensive treatments. Altogether, these patients account for less than 10% of all cases of hypertension. The most sensitive test in this group is measurement of urinary metanephrines. Among 30 patients with phaeochromocytoma in whom urinary metanephrines and plasma noradrenaline were measured on the same day, none had urinary metanephrine values lower than 3.69 mumol/24 h (0.7 mg/24 h) while 6, who had normal blood pressure at the time of sampling, had noradrenaline levels below 3.53 nmol/l (600 pg/ml). Prior to surgery, the tumour was correctly located by urography (69% of 58 n = tumours), ultrasounds (74%, n = 38), arteriography (83%, n = 23), radioisotope scanning (91%, n = 32), computed tomography (95%, n = 40) and nuclear magnetic resonance imaging (12/12). In 28 patients who had both radioisotope scanning and computed tomography the sensitivities of these examinations were 90% and 100% respectively. A stage by stage approach to the diagnosis of phaeochromocytoma, using detection criteria followed by biochemistry then location methods, is an economical strategy with the best yield from diagnostic and imaging techniques.