Skin lesions. LCH skin lesions in patient no. 2 disappeared after a few days of treatment with vemurafenib. Skin biopsy before treatment showing typical LCH infiltration of the epidermis and papillary dermis with CD1a⁺ histiocytes; the hypodermis is infiltrated by foamy CD68⁺CD1a⁻ histiocytes (as in the peritoneal biopsy). Immunohistochemistry confirmed the expression of BRAF by histiocytes.