Multiple endocrine neoplasia

Abstract

Multiple endocrine neoplasia (MEN) describes the occurrence of tumours affecting two or more endocrine glands in one individual. Two main forms are recognized: type 1 (MEN1) and type 2 (MEN2). MEN1 is characterized by the combined occurrence of parathyroid, pituitary and pancreatic neuroendocrine tumours, whereas MEN2 features medullary thyroid cancer in association with phaeochromocytoma and parathyroid tumours. Although both MEN1 and MEN2 are autosomal dominant disorders, they have contrasting molecular aetiologies: MEN1 results from inactivating germline mutations of the MEN1 tumour suppressor gene, whereas MEN2 results from activating mutations in the RET proto-oncogene. The clinical features arising in each condition relate to the location of tumour development and/or hormonal hypersecretion, while treatment approaches aim to minimize morbidity and mortality, and preserve quality of life. Genetic testing is a key component of management, both to confirm the diagnosis in affected individuals, and to identify family members who are at risk of disease but may be asymptomatic. It is recommended that those ‘at risk’ of developing MEN1 or MEN2 (i.e. mutation carriers) undergo periodic clinical, biochemical and radiological surveillance for the early identification and/or treatment of tumours. Here, a brief overview of MEN1 and MEN2 is provided.