MEN III, also known as MEN IIb, is characterized by medullary thyroid carcinoma, pheochromocytoma, and mucosal neuromas.Wermer's syndrome is also called MEN type I . It is characterized by pancreatic (insulinoma), pituitary, and parathyroid involvement.Sipple's syndrome, or MEN type II , is similar to MEN III, but it has parathyroid involvement (tumor or adenoma) as opposed to neuromas. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 18. Endocrine Pathology. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.