Preschooler with new onset diabetes insipidus

MRI of Langerhans cell histiocytosis of the pituitary
Sagittal T1 MRI without contrast (above left) of the brain shows absence of the posterior pituitary bright spot. Sagittal (above right) and coronal T1 with contrast (below left) show a thick and enhancing pituitary stalk. Axial T1 with contrast (below right) again shows the thick enhancing pituitary stalk and enhancing lesions in both sphenoid wings and in the left orbit.

The diagnosis was Langerhans cell histiocytosis of the pituitary and Langerhans cell histiocytosis of the orbit.