ABSTRACT
Most tumors of the endocrine system are sporadic and arise within a single gland. However, the multiple endocrine neoplasia (MEN) syndromes are characterized by a predisposition to develop neoplasms in multiple endocrine glands. As in other heritable cancer syndromes, the tumors may be multifocal and bilateral, synchronous or metachronous, and tumor histology varies from hyperplasia to invasive, metastasizing carcinoma.
