A case of acromegaly accompanied by adrenal preclinical Cushing's syndrome

We encountered a 58-year-old woman with acromegaly accompanied by a cortiso l-secreting adrenal tumor without clinical features of hypercortisolism. Th e simultaneous occurrence of these two endocrinopathies in one individual i s extremely rare. She was diagnosed as having diabetes mellitus 8 years ago . Afterwards, in spite of insulin therapy, her hyperglycemia could not be w ell controlled. Her acromegaly and preclinical Gushing's syndrome were hist opathologically proven to be due to a pituitary adenoma and an adrenocortic al adenoma, respectively. Successful treatment for these endocrinopathies r esulted in greatly improved blood sugar control because of a reduction in i nsulin resistance. In this case of preclinical Gushing's syndrome, replacem ent therapy with glucocorticoid was able to be discontinued at only 8 weeks after adrenalectomy, so that the period of necessary replacement was much shorter than that for overt Gushing's syndrome. This is the first report de scribing insulin resistance before and after treatment in a case of acromeg aly accompanied by adrenal preclinical Gushing's syndrome.