Background: Erdheim Chester disease (MEC) is a rare non-Langerhans cell histiocytosis characterized by multi-visceral involvement. We report a case of MEC associated with Langerhans cell histiocytosis (HCL).
Case report: A 46-year-old women presented skin and vulvar localization of HCL associated with typical MEC bone involvement. Despite chemotherapy (vinblastine) and prednisone, the disease progressed to involve the central nervous system, leading to fatal outcome. Post-mortem examination showed HCL in skin, MEC in bones and central nervous system, and intermediate histiocytic proliferation in the encephalon.
Discussion: Usually, MEC and HCL are considered as distinct entities. MEC is characterized by a xanthogranulomatous proliferation of CD 68+ foamy histiocytes nested in fibrosis, and HCL by a proliferation of PS 100+ and CD1a+ Langerhans cells. However, our observation, as well as previous reports, suggests that MEC is part of the HCL spectrum.