CD1A and sinus histiocytosis with massive lymphadenopathy: Finally, we obtained the pathological diagnosis of RDD using IHC as follows: CD68+, CD163+, S‐100+, CyclinD1 (scattered +), CD1α‐, CD21‐, CD23‐, CD35‐, Langerin‐, Braf (V600E)‐, BRAF‐, SSTR‐, CD3‐, CD20‐, CD20‐, Ki‐67 (scattered +), and EBER CISH‐ (Figure 3).