Cerebellar and basal ganglion involvement in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a disease of unknown cause character ised by proliferation of histiocytic granulomas in tissues; the primary cer ebral manifestation is diabetes insipidus caused by hypothalamic infiltrati on. We present a patient in whom, except for the absence of high signal on T1 weighting in the posterior pituitary, consistent with central diabetes i nsipidus. MRI showed no evidence of hypothalamic involvement by histiocytos is, despite the long duration of the disease. However, there was bilateral, symmetrical involvement of the cerebellum and globus pallidus in addition to a calvarial lesion. High signal in the cerebellar white matter on T2-wei ghted images may represent demyelination, gliosis and cell loss, as previou sly reported on pathologic examination.