Dramatic Improvement of Diabetes Mellitus Following the Treatment of Coexisting Acromegaly and Cushing's Syndrome

Endocrine diseases are frequently accompanied by diabetes mellitus and treatment of an underlying endocrine disease often improves glucose control. The co-occurrence of acromegaly and Cushing's syndrome is extremely rare. We herein describe a patient who showed a dramatic improvement in glucose control following treatment for co-existing acromegaly and Cushing's syndrome. An adrenal mass was incidentally discovered during a routine evaluation of a 56-year-old woman who was subsequently diagnosed with acromegaly and a unilateral cortisol-producing adrenal adenoma. Her blood glucose was poorly controlled despite receiving high-dose insulin therapy. After undergoing adrenalectomy for Cushing's syndrome, her insulin dosage was decreased by almost 50%. The insulin treatment was discontinued following the treatment of acromegaly.