Phaeochromocytoma - An update

Abstract

Phaeochromocytoma is a rare catecholamine-secreting neuroendocrine tumour of the c:hromaffin cells which occurs predominantly in the adrenal medulla. To date, germline mutations in five genes have been isolated and implicated in familial phaeochromocytomas. The syndromes include von Hippel-Lindau syndrome, multiple endocrine neoplasia type 2 syndrome, and neurofibromatosis type 1 syndrome. More recently familial paraganglioma syndromes have been described in which mutations of the genes encoding succinate dehydrogenase subunits B, C and D occur. The presenting features of phaeochromocytomas are due to the catecholamine excess and are variable in their expression as there is diversity in the phenotypes of these tumours. These tumours may result in severe morbidity and mortality from cardiovascular complications ranging from a typical paroxysmal pattern of hypertension to overt cardiac failure and sometimes sudden death. Diagnosis of phaechromocytoma requires the biochemical confirmation of excessive catecholamine production based on measurement of either catecholamines or their metabolites in the plasma or urine, following which the tumour is localised using imaging studies. The measurement of plasma free metanephrines has recently become available for routine use. This test has generated much controversy, but has been advocated as the test of choice in many studies. The management of a phaeochromocytoma is mainly surgical and requires careful patient preparation to avoid catecholamine-induced complications during surgery. This review provides an update on phaeochromocytomas.