Although the mutation frequency is much lower than that in LCH, JXG, and ECD, RDD involves mutations in the MAPK/ERK pathway, encompassing genes such as KRAS, NRAS, MAP2K1, ARAF, CSF1R, and on rare occasions, BRAF V600E [6, 52, 62, 76]. This evidence concerns the gene BRAF and sinus histiocytosis with massive lymphadenopathy.