MEN–multiple endocrine neoplasia
MEN type 1–I A complex characterized by pituitary adenoma or hyperplasia, adrenal adenoma or hyperplasia, parathyroid adenoma or hyperplasia, acromegaly, pancreatic islet cell tumors–insulinoma, carcinoid, Zollinger-Ellison syndrome, WDHA syndrome, ↑ gastrin secretion, peptic ulcer, Note: Nonhereditary factors may influence the expression of MEN I as the condition may be unequally expressed in identical twins; the defective gene is located on chromosome 11q13 Lab Invest 1995; 72:494
MEN type 2a–I/IIa A complex characterized by medullary carcinoma of the thyroid–bilateral and present in nearly 100% of cases producing calcitonin, histaminase, prostaglandins, ACTH, potentially causing Cushing syndrome, pheochromocytoma and parathyroid adenoma or hyperplasia Diagnosis Conventional diagnostic modalities–eg radiologic imaging, histopathology, and laboratory values–↑ plasma calcitonin, ↑ urinary catecholamines, and catabolites, for MEN-2A identifies relevant tumors, but not carriers Molecular pathology The MEN-2A gene mutation identified by linkage analysis in the RET proto-oncogene, which maps to chromosome 10q11.2, specifically at exon 10 or 11, is highly specific–no false positives and highly sensitive–no false negatives, allowing early diagnosis of MEN-2A. See.RET gene Prognosis Excellent
MEN type 2b–III/IIb Mucosal neuroma syndrome A complex characterized by bilateral medullary carcinoma of the thyroid–producing calcitonin, histaminase, prostaglandins, ACTH and potentially, Cushing syndrome, pheochromocytoma, parathyroid adenoma or hyperplasia, mucosal–gut neurofibromas, associated with thickened lips, submucosal oral nodules, intestinal ganglioneurofibromatosis, infantile intestinal dysfunction and cranial nerve hyperplasia and connective tissue disease–Marfanoid habitus, scoliosis, kyphosis, pectus excavatum Prognosis 20% mortality