Langerhans cell histiocytosis of hypothalamus and optic chiasm: CT and MR studies.

The clinical, CT, and magnetic resonance features of two cases of hypothalamic/optic chiasm involvement with Langerhans cell histiocytosis are presented. In both cases, the mass was iso- to hyperdense on noncontrast CT with uniform postcontrast enhancement, whereas with magnetic resonance (one case) the mass remained isointense to brain on both long and short repetition time sequences. The pathophysiology of hypothalamic pituitary dysfunction is briefly reviewed.