Dear Editor, Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis (LCH), disorder listed under the "R group" of histiocytosis including familial and sporadic forms by the Histiocyte Society. Mutations in I MAP2K1 i have been associated with LCH and RDD and mutually exclusive somatic mutations in I KRAS i and I MAP2K1 i with RDD [[1], [8]]. Though somatic I MAP2K1 i mutation might have been crucial in RDD pathogenesis in this patient, likely pathogenic and heterozygous I SLC29A3 i mutation might have been contributory as well. [Extracted from the article]