Challenging Management of Erdheim-Chester Disease: A Case Report

Erdheim-Chester Disease (ECD) is a type of systemic histiocytosis mostly observed in adults, characterized by the infiltration of foamy CD68+ and CD1a- histiocytes into multiple organ systems, often associated with MAPK pathway mutations. Conventional treatment of ECD has been challenging. Currently, targeted drugs (BRAF and MEK inhibitors) are recommended. This report aimed to describe the necessity of targeted therapy for ECD. A 39-year-old Japanese man presented with complaints of weight loss, polyuria/polydipsia, bilateral leg pain, and facial xanthoma/xanthelasma palpebrarum (XP) lesions. A biopsy of the bone lesions confirmed BRAF-positive ECD. The ECD lesions initially showed a good response to the cladribine/dexamethasone regimen; however, XP lesions were exacerbated during infliximab therapy, and did not respond to other conventional regimens. Eventually, XP lesions improved with trametinib (a MEK inhibitor) and dabrafenib (a BRAF inhibitor). Targeted therapy is indispensable in the management of ECD.