Lymphocytic infundibuloneurohypophysitis presenting as diabetes insipidus in a man.

We report a patient with diabetes insipidus, whose sella magnetic resonance imaging revealed a normal hypophysis with a focal nodular thickening of the infundibulum and lack of hyper-intense signal of the normal neurohypophysis. The histopathologic examination of the lesion showed a lymphoplasmacytic, predominantly lymphocytic, infiltration. A diagnosis of lymphocytic infundibuloneurohypophysitis was made, by the exclusion of other infiltrative, granulomatous diseases.