Cutaneous Rosai‐Dorfman Disease With MAP2K1 Mutation Treated With Encorafenib and Binimetinib

Rosai‐Dorfman disease (RDD) is a rare histiocytic disorder with unifocal to multisystemic involvement. Activating mutations in the MAPK/ERK pathway can occur in up to 50% of RDD cases. We report a case of cutaneous RDD (C‐RDD) with facial and truncal lesions harboring an activating MAP2K1 (MEK1) mutation that showed a complete response to a combined treatment with MAPK inhibitors encorafenib and binimetinib. This case suggests that MAPK inhibitors may represent a therapeutic option for C‐RDD in certain cases.