Question: What is Nelson's syndrome?

Answer: Up to 10% of patients who have had a bilateral adrenalectomy for the cure of pituitary Cushing's can develop Nelson's syndrome. This syndrome refers to the enlargement of the pituitary tumor after removal of both adrenal glands. Bilateral adrenalectomy was the primary treatment for pituitary Cushing's prior to the 1970's. However, since that time, transsphenoidal surgery is able to cure 80-90% of patients with Cushing's disease if the surgery is performed by an experienced pituitary neurosurgeon. For this reason, bilateral adrenalectomy is not often necessary, meaning that the incidence of Nelson's syndrome is now fairly low.