Langerhans cell histiocytosis affecting pituitary infundibulum

Axial (image 1), coronal (image 2), and sagittal (image 3) T1-weighted post-contrast MRI focused on the pituitary show thickening of the infundibulum (arrow) and enlargement of the pituitary (arrowhead). Langerhans cell histiocytosis rarely affects the central nervous system. When it does, patients may present with diabetes insipidus, ataxia, or hydrocephalus. Diabetes insipidus is a common manifestation when the posterior pituitary and infundibulum are infiltrated by Langerhans cells. Infundibular thickening greater than 3 mm is suggestive of involvement.