This case report deals with an insulin-dependent diabetic patient suffering peripheral adrenal insufficiency who, after 12 years of substitutive treatment exhibited resistance to mineralo- and gluco-corticoids with relapse of melanodermia and plasma ACTH levels higher than 1500 pg/ml despite increasing doses. A corticotrop macroadenoma was diagnosed by MR imaging and functional tests and confirmed by surgical excision followed by disappearance of resistance. Pre-operative functional investigation show autonomisation of the adenoma but with some partial persisting regulation. This case report draws attention to this rare either complication or association which can occur in peripheral adrenal insufficiency.