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: Pediatrics
All are involved in MEN IIA except: 
Select and explain. 
A. Pituitary, B. Parathyroid, C. Thyroid, D. Adrenal
A: Pituitary
Answer: A: Pituitary 
Explanation: a. Pituitary(Ref: Nelson's 20/e p 2694-2481, Ghai 8/e p 523)In Multiple Endocrine Neoplasia (MEN) IIA, features seen are: "HAPPY", i.e. Hirschsprung disease, Amyloidosis, Pheochromocytoma, Parathyroid hyperplasia/Adenoma and thyroid Carcinoma (Medullary).