Considering the combination of <i>GNAS</i> mutation with one of the typical clinical triad characteristics, fibrous dysplasia of bone, we diagnosed this patient with McCune-Albright syndrome accompanied by ACTH-independent Cushing's syndrome caused by an ectopic residual adrenal tumor due to <i>GNAS</i> mutation. Here, POMC is linked to Cushing syndrome due to macronodular adrenal hyperplasia.