Two steps are classically used in the diagnostic approach to Cushing's syndrome: the first establishes that chronic hypercortisolism is present, and the second identifies its precise cause with its specific prognostic and therapeutic implications. This latter step requires sophisticated basal and dynamic hormonal evaluations, as well as imaging procedures directed at the pituitary and the adrenals.
The main goal of adrenal imaging in Cushing's syndrome is to look for a tumoral lesion. The technique of choice is the CT scan, since no adrenocortical tumor large enough to cause Cushing's syndrome can escape its detection power.
In ACTH-dependent Cushing's syndrome, as a rule the two glands are moderately and symmetrically enlarged. However, pathological examination of the glands shows the frequent occurrence of micronodular lesions which in some cases are large enough to be visible to the naked eye: this stage corresponds to what is called—somewhat arbitrarily—macronodular hyperplasia, and it is found