Bone curettage samples in Erdheim-Chester disease

Bone curettage samples (panels A and B) from a patient with Erdheim-Chester disease demonstrate tissue infiltration by sheets of foamy (xanthomatous) histiocytes with interspersed inflammatory cells and multinucleate giant cells (Touton cells). The histiocytes express the histiocyte markers CD68 (panel C) and CD163 (panel D), but do not express CD1a (panel E) or Langerin (panel F).