T1 post-gad T1 post-gad T2

Diagnosis: Langerhans cell histiocytosis

Central nervous system Langerhans cell histiocytosis classically presents as an infiltrative, enhancing mass involving the hypothalamus and pituitary infundibulum. Parenchymal or dural masses may also be present. Patients are usually children and may present with diabetes insipidus. The differential diagnosis of this case includes CNS, lymphoma, sarcoidosis, and metastases. The involvement of the hypothalamus and pituitary infundibulum might tip you off to consider either sarcoid or Langerhans cell histiocytosis. Histiocytosis is last in the differential since this is such an unusual appearance. Related Cases

Grois N, Tsunematsu Y, Barkovich AJ, Favara BE. Central nervous system disease in Langerhans cell histiocytosis. Br J Cancer Suppl, Sep 1994; 23: ps24-8.

Tien RD, Newton TH, McDermott MW, Dillon WP, Kucharczyk J. Thickened pituitary stalk on MR images in patients with diabetes insipidus and Langerhans cell histiocytosis. AJNR, Jul-Aug 1990; 11(4):p703-8.

CNS Lymphoma Neurosarcoidosis Histiocytosis