Evolving Concepts In The Diagnosis, Prognosis, And Treatment Of Pheochromocytoma

Introduction.-Pheochromocytoma is a catecholamine-secreting neoplasm of chromaffin tissue. It is a rare disease. Biochemical tests should be performed only in patients at high risk of pheochromocytoma, and an imaging procedure only in those with positive biochemical tests.Current knowledge and key points.-The most specific and sensitive diagnostic test for the disease is the determination of plasma or urinary metanephrines. The tumor can be located by computerized tomography, magnetic resonance imaging, and specific scintigraphy. Ten to 20% of pheochromocytomas result from hereditary diseases, including multiple endocrine neoplasia type 2, von Hippel Lindau disease, and neurofibromatosis 1. Familial cases are diagnosed earlier, and are more frequently bilateral and recurring than sporadic cases. About 10% of the cases are malignant either at first operation or during follow-up, malignancy being diagnosed by the presence of lymph node, visceral or bone metastases. The probability of a recurrence is positively correlated with the urinary excretion of metanephrines and tumor size. Recurrences are more frequent in cases with ectopic tumors and in those with a low plasma epinephrine to total catecholamine ratio. Patients, especially those with familial tumors or low epinephrine secretion, should be followed-up indefinitely.Future prospects and projects.-Treatment for malignant recurrences includes surgery therapeutic embolization, chemotherapy, and the application of therapeutic doses of metaiodobenzylguanidine. Metyrosine, phenoxybenzamine, or somatostatin analogs may help to control blood pressure and to alleviate symptoms in patients with malignant pheochromocytoma; however such a treatment has no antiproliferative effect. (C) 2000 Editions scientifiques et medicales Elsevier SAS.