POMC and adenoma: Except for the five ACTH-secreting adenomas in the series of Ratliff, where MRI was non-diagnostic (29), a finding which is in agreement to up to about 40% of cases of Cushing’s disease having normal MRI (71), a single tumor image or, alternatively, ill-defined abnormalities, such as an asymmetric, inhomogeneous appearance of the gland (55) or a global increase in the pituitary volume (30) were noted in most patients, which might prompt the neurosurgeon to careful exploration of the gland.