Clinical and genetic aspects of phaechromocytoma

Phaeochromocytoma is a tumour of the adrenal medulla, which, although rare, is a major cause of correctable hypertension with a prevalence of 0.1-0.5% in the hypertensive population. Clinical symptoms include attacks of paroxysmal headache, sweating, palpitations, stress and a sense of imminent death. Often associated with the above is an increase in blood pressure. Despite the fact that the underlying genetic mechanisms of phaeochromocytoma have been well investigated, they are still incompletely understood. In approximately 80% of cases the tumour occurs sporadically, but it may occur in association with type 2 multiple endocrine neoplasia, type 1 neurofibromatosis or von Hippel-Lindau disease. Molecular evidence suggests that other genes such as SDHD or SDHB may control its development; the possibility of other putative phaeochromocytoma genes is currently being investigated.