Multiple endocrine neoplasia type 1 (MEN1).

Multiple endocrine neoplasia type 1 (MEN1) is inherited in an autosomal dominant fashion and predisposes to the development of hyperplastic or neoplastic changes in the parathyroid and pituitary glands and the endocrine pancreas, along with numerous other characteristic tumors and features. The management of each entity differs to some degree from their sporadic counterparts, while the lack of a genotype-phenotype correlation requires lifelong clinical, biochemical and radiological screening for the development of new tumors. While the syndrome itself is relatively rare (a prevalence of 1-10/100 000), it is likely that health-care practitioners from numerous specialities will occasionally encounter a patient with MEN1 and therefore a basic knowledge of the syndrome is important. In addition, many of the associated tumors are seen commonly in sporadic form, and a judicious policy is therefore required in deciding how thoroughly patients who develop these tumors should be screened for MEN1. The current literature on MEN1 is reviewed and key learning points are suggested for the clinician.