Phaeochromocytoma: state-of-the-art

Abstract

Phaeochromocytomas are catecholamine-secreting tumours that arise from chromaffin cells of the adrenal medulla and extra-adrenal sites. Extra-adrenal phaeochromocytomas are called paragangliomas. A diagnosis of phaeochromocytoma is suspected by typical paroxysmal symptoms, unusual or refractory hypertension, discovery of an adrenal incidentaloma or a family history of phaeochromocytoma or paraganglioma, possibly associated with other genetic syndromes (multiple endocrine neoplasia type 2 A or B, neurofibromatosis type 1 and von Hippel-Lindau disease). It can be confirmed by measurements of urinary or plasma fractionated catecholamines and metanephrines. The best diagnostic performances are achieved by metanephrines. Twenty-four hour urine fractionated metanephrines are still recommended as a screening test but some experts prefer plasma measurements in high-risk patients. Increased serum chromogranin-A levels, combined with high catecholamine or metanephrine in a patient with normal renal function is also a tool, virtually diagnostic of phaeochromocytoma. Recent studies have suggested that 25% of patients with phaeochromocytoma have germline mutations of several genes (NF1, VHL, SDHD, SDHB and RET). Thus, genetic testing should be carried out according to an algorithm of risk factors and specific characteristics. Once a biochemical diagnosis of phaeochromocytoma is made, a CT scan or MRI of the abdomen and pelvis should be performed first. If these investigations remain negative, the chest and neck should be explored. After anatomical imaging, functional imaging by 123I-MIBG should be considered. If the MIBG scan is negative, other imaging modalities have recently proven to be useful (PET, Octreoscan). After localization, the treatment of phaeochromocytoma is a surgical resection, which may be laparoscopic. Preoperative preparation with alpha- and beta-adrenergic blockade and/or calcium channel blockers associated with volume expansion is essential. Malignant phaeochromocytoma is rare and its treatment still unsatisfying. Phaeochromocytoma during pregnancy is also rare and its diagnosis easily missed because of its clinical resemblance to pre-eclampsia.