Hypothalamic Langerhans cell histiocytosis with no eosinophils.

A 26-year-old man presented with diabetes insipidus, sexual dysfunction and memory impairment. Nuclear magnetic resonance imaging and pathologic examination revealed Langerhans cell histiocytosis of the hypothalamus, which contained no eosinophils. The lesional cells were positive for S-100 protein and CD1a antigen, and negative for CD68 antigen. The possible pathogenesis, absence of eosinophils and prognosis are discussed.