However, extracutaneous JXG lesions with mitogen activated pathway kinase (MAPK) / extracellular-signal-regulated kinase (ERK) pathway activating mutations are now categorized into the Langerhans “L-group” histiocytosis, including three rare BRAF V600E JXG “L-group” neoplasm [56]. The gene discussed is BRAF; the disease is Histiocytosis.