Familial endocrine tumours: pheochromocytomas and extra-adrenal paragangliomas – an update

Pheochromocytomas (PCC) and paragangliomas (PGL) are tumours occurring in the adrenal medulla and in extra-adrenal paraganglia, respectively. They have long been associated with familial occurrence and several syndromes had been described in which PCC formed an important component, including multiple endocrine neoplasia type 2, von Hippel-Lindau disease and neurofibromatosis type 1. Since the beginning of this millennium, both by the elucidation of specific genes, such as the various succinate dehydrogenase genes, as well as by generic molecular biology approaches, such as The Cancer Genome Atlas (TCGA) initiative, it was shown that the frequency of germline mutations in candidate genes for PCC and PGL has increased to 35–40%. In addition, somatic mutations have been shown to be much more frequent than previously thought, such that now 60–65% of these tumours harbour either a germline or a somatic mutation. This review gives an overview of the various syndromes and the genes involved, concluding with recommendations for genetic testing in the current era of genome wide analysis.