This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
Enlargement of pituitary tumor after adrenalectomy is called as: 
Select and explain. 
A. Nelson syndrome, B. Steel-Richardson syndrome, C. Hamman-Rich syndrome, D. Job's syndrome
A: Nelson syndrome
Answer: A: Nelson syndrome 
Explanation: Nelson Syndrome: Nelson syndrome refers to a spectrum of symptoms ansd signs arising from an adrenocoicotropin (ACTH)- secreting pituitary macroadenoma after a therapeutic bilateral adrenalectomy The spectrum of clinical features observed relates to the local effects of tumors on surrounding structures , the secondary loss of other pituitary hormones, and the effects of the high serum concentrations of ACTH on the skin Ref: Harrison 19th edition PGno: 2273