A decrease in the dose of pegvisomant was needed for the treatment of acromegaly after adrenalectomy in a patient with coexisting preclinical Cushing's syndrome.

We herein describe the case of a 47-year-old woman with pre-clinical Cushing's syndrome caused by a left adrenal adenoma, which was diagnosed 6 years after trans-sphenoidal selective removal of a pituitary adenoma for acromegaly at age 35. The patient was started on bromocriptine and then somatostatin analogues after the surgery; however, since her serum insulin-like growth factor-1 (IGF-1) values remained above the age-adjusted normal range, the treatment for acromegaly was switched from somatostatin analogues to pegvisomant (10 mg daily), before a left laparoscopic adrenalectomy. After the subsequent adrenalectomy, the dose of pegvisomant could be reduced gradually to once every 4 days without any increase in the serum IGF-1 values. This is the first report describing the need for a different dose of pegvisomant for the treatment of acromegaly before and after adrenalectomy for pre-clinical Cushing's syndrome.