[Skin manifestations of Erdheim-Chester disease. Case report and review of the literature].

A 46 year old woman suffering from Erdheim-Chester disease is reported for the first time in the German dermatologic literature. She showed periorbital xanthelasmas and indurated erythemas on both flanks. Histologically the skin manifestations were also a sign of the basic disease which had spread to various organs. Small granulomas with foam cells, macrophages and few giant cells were found in the corium. Immunohistochemistry demonstrated positive reactions to protein S-100 and alpha-1-Antichymotrypsin, while CD 1 a-antigen and PNA were negative. Further localizations of Erdheim-Chester disease were found in the femurs, tibiae and mandibula as well as in the right breast, retroorbital region and abdominal aorta. Infiltration of the retroperitoneal cavity led to urinary retention and nephrectomy. With systemic corticosteroid therapy, the skin lesions on the flanks regressed but recurred after discontinuance of the drug. Erdheim-Chester disease is now classified as part of the histiocytoses which is confirmed by our immunohistochemical findings. The histiocytes are probably not identical with Langerhans cells. The diagnosis is usually made by the radiologist on the basis of typical osteosclerotic symmetrical lesions of the long bones, histologically representing lipoid granulomas. Common non-osseous manifestations of the disease are in the retroperitoneal region, orbita and intracranially (partially associated with diabetes insipidus) which are often fatal. On the skin, xanthelasma and xanthoma are present in 1/6 of the cases; in some patients yellow-brown papular and widespread infiltrated lesions have been described. As regards to therapy corticosteroids chemotherapy, radiation and immunomodulating agents as well as surgery have been used with limited success.