Non-iatrogenic Cushing's syndrome has been associated primarily with three entities: pituitary-dependent processes due to pituitary adenomas or microadenomas causing adrenal hyperplasia; pituitary-independent primary adrenal causes, predominantly unilateral adenomas, rarely multiple adenomas or adrenal carcinoma; ectopic sources of adrenocorticotropic hormone (ACTH) production. Although non-neoplastic bilateral adrenal disease generally has been ascribed to extra-adrenal stimulation, a rare cause of Cushing's syndrome that involves bilateral adrenal nodule formation independent of pituitary stimulation has been identified. Nodular adrenal diseases represent a confusion of terms in the literature, but one subgroup of Cushing's syndrome has most frequently--and, perhaps, most appropriately--been designated primary adrenocortical nodular dysplasia. A case of this unusual entity is presented, and previous case reports pertaining to this confusing area of adrenal hyperfunction are reviewed. The characteristic manifestations that separate this diagnosis from other types of nodular adrenal disease are also discussed. Recognition of this diagnosis, although rare, is important, as bilateral adrenalectomy in the treatment of choice.