This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
All of the following are features of MEN IIb, except - 
Select and explain. 
A. Pituitary tumor, B. Pheochromocytoma, C. Medullary carcinoma thyroid, D. Neuromas
A: Pituitary tumor
Answer: A: Pituitary tumor 
Explanation: MEN 2A is characterised by Medullary Thyroid Carcinoma (90%), Pheochromocytoma (>50%) and Parathyroid adenoma (10-25%).MEN 2B (also known as MEN 3) is characterised by MTC (>90%), Pheochromocytoma (>50%) and associated abnormalities (40-50%) - mucosal neuromas, marfanoid habitus, medullated corneal nerve fibres, megacolon. Reference : page 2336 Harrison's Principles of Internal Medicine 19th edition