Pheochromocytomas and paragangliomas are rare tumors, characterized by catecholamine synthesis, release, and metabolism, with the same embryological origin. Pheochromocytomas develop from chromaffin cells of the adrenal medulla, whereas paragangliomas arise extra-adrenal from sympathetic and parasympathetic nervous chains. During the past 10 years, there have been significant advances in the understanding of these tumors as it is now known that 30–40% of pheochromocytomas and paragangliomas have an underlying genetic cause. Pheochromocytomas and paragangliomas have classically been associated with three syndromes: von Hippel-Lindau (VHL), multiple endocrine neoplasia type 2 (MEN 2), and neurofibromatosis type 1 (NF1). To date, more than 21 gene mutations have been identified that are involved in the development of these tumors. Identification of such gene mutations associated with pheochromocytomas and paragangliomas will ensure early diagnosis, prompt treatment, and better prognosis for patient and family members. The recent developments in molecular pathogenesis of pheochromocytomas and paragangliomas will provide future treatment options toward personalized therapy for patients. This chapter summarizes the most important aspects of genetics and clinical characteristics, together with a focus on the new susceptibility genes.
Part of the book: Clinical Management of Adrenal Tumors