MR of pituitary metastasis in a patient with diabetes insipidus.

We present a case of acute-onset diabetes insipidus in a 69-year-old man who had been treated for lung cancer. T1-weighted MR images showed a thickened pituitary stalk and absence of the normal high intensity of the posterior pituitary lobe. Dynamic imaging demonstrated poor enhancement in the posterior lobe, whereas the anterior lobe was strongly enhanced. Autopsy revealed that metastatic tumor from lung cancer had infiltrated the posterior lobe as well as the pituitary stalk.