Skin Involvement by Erdheim-Chester Disease; A Case Report

Abstract Introduction/Objective Erdheim-Chester Disease (ECD) is considered one of the rare forms of non-Langerhans cell histiocytosis. It is caused by infiltration of different organs with lipid-laden histiocytes with foamy cytoplasm. Clinically, it can present as an indolent localized disease or a fatal disease with multi-organ failure. Methods/Case Report Here we report a case of fifty year-old female with a history of Erdheim Chester disease involvement of the left parietal lobe presented to the dermatology clinic with purpuric, tender maculopapular rash on bilateral cheeks, trunk, and bilateral upper extremities. Biopsy of the lesion on central chest revealed acute and chronic superficial dermal inflammation and skin crusting. The dermis is also infiltrated by many foamy lipid-laden macrophages. These macrophages stained with CD68 and CD163 and were S-100 and CD1a negative. BRAF V600E mutation was detected. Based on the immunophenotypic characteristics, as well as the molecular testing results and the clinical history of the patient, diagnosis of cutaneous involvement by Erdheim- Chester disease was made. Results (if a Case Study enter NA) NA Conclusion In summary, despite the fact that skin involvement by Erdheim- Chester disease is rare, it is imperative to consider it in the differential diagnosis of histiocytic diseases affecting the skin and differentiate it from its histologic mimickers. Molecular testing is a helpful tool in the diagnosis of Erdheim-Chester disease. Accurate diagnosis is crucial for guiding treatment plans.