Here we describe a case of Neurofibromatosis type 1 (NF1) associated with an atypical histiocytic lesion and a new pathogenic mutation. The genetic analysis revealed an heterozygous mutation in the 5' splice site of intron 32, 6,084 + 1G -> T. Histopathological findings are compatible with juvenile xanthogranuloma. The new, not already described, splicing mutation, is possibly partly responsible of the association between NF1 and the histiocitic lesion.