A paroxysmally secreting phaeochromocytoma: Biochemical and clinical aspects

Abstract

Summary.One of the problems encountered with the diagnosis of a paroxysmally secreting phaeochromocytoma is the failure of the conventional chemical screening tests to demonstrate an increased urinary excretion of catecholamines and/or their metabolites. The usefulness of the estimation of plasma catecholamines in the diagnosis of this kind of phaeochromocytoma is demonstrated in a 64 years old male patient. In addition the mode of secretion of catecholamines from this phaeochromocytoma was investigated.The patient suffered from paroxysms characterized by the feeling of pressure in the throat, pain in the substernal area, palpitations, hypertension, flush and headache. Because of a normal excretion of catecholamines and vanillylmandelic acid in the 24-h collection of urine, estimated on several occasions, a phaeochromocytoma was excluded for about 6 years. The existence of a phaeochromocytoma could be verified by the measurement of plasma catecholamines. The plasma levels of noradrenaline and adrenaline in symptom-free intervals several days previous to the removal of the phaeochromocytoma were comparable to the levels found postoperatively up to 2.5 months. However, during 3 paroxysms highly elevated plasma levels of noradrenaline (up to 21.3 ng/ml) with only a moderate increase of adrenaline (up to 0.54 ng/ml) were measured. After removal of the predominantly noradrenatine producing tumor, which was localized in the right adrenal gland, the paroxysms disappeared.Dopamine/?-hydroxylase activity in plasma as a marker of an exocytotic release mechanism neither increased during a paroxysm nor decreased * This work was supported by the Jubil/iumsfond of the ~ster-reichische NationalbankOffprint requests to: Dr. Heide H6rtnagl (address see page 607) postoperatively. Biochemically the paroxysmally secreting phaeochromocytoma was characterized by a high storage capacity for catecholamines, by a proportionate release from noradrenaline and adrenaline producing cells and by a release mechanism which is based on diffusion of the catecholamine out of the cell rather than on exocytosis.

Incidental Adrenal Mass Hampers the Diagnosis of an Extra-Adrenal Phaeochromocytoma

“…Brief cate cholamine surges, resulting in normal 24-hour urinary concentrations but elevated plasma catecholamine levels during paroxysms are rare findings in phaeochromocyto ma [4], We hypothesise that urinary excretion of catechol amines was reduced during adrenal crisis due to renal vasoconstriction caused by excessive noradrenaline re lease. Plasma noradrenaline was rapidly eliminated by either neuronal uptake or increased clearance across the lungs and hepatomesenteric circulation.…”