We report a case of massive cerebral infarct in the early stage of pituitary apoplexy. The case is unique because the stroke was delayed and occurred only after the patient developed severe arterial hypotension superimposed on a tandem internal carotid artery stenosis by both the sellar mass on the siphon and an unknown homolateral atheromatous cervical lesion. Illustrated with MRI and specifically by diffusion-weighted imaging, this case reinforces the idea that a low apparent diffusion coefficient in a non-enhancing sellar mass may indicate the presence of pituitary apoplexy and help in the early adequate management of such patients.