Bilateral malignant polyadenomas of adrenals seem to be rare. They involve either a double primary adrenal tumour, or a metastasis of a controlateral tumour. In the observation reported here, the evolution is characterized by periods of central stimulation with partial autonomy, and periods of tumoral autonomy with central inertness. Pathological findings consist of coexistence of various histological aspects (atrophy, hyperplasia, benign adenoma, carcinoma) suggesting the successive steps of a very particuliar adrenal carcinogenesis. Such findings allow to discuss the following physiopathological mechanism: a stimulation by ACTH might have resulted initially in a preneoplasic hyperplasia, then in an incompletely autonomous tumour, and finally in an autonomous tumour. Accordingly, from a practical and therapeutic point of view, it would be suitable, after removal of an adrenal tumour, especially of one with demonstrated ACTH-dependance, to suppress totally endogenous ACTH by cortisol or cortisone therapy, in order to reduce the occurence of corticotropin stimulation of possibly remaining malignant adrenal cells.