Fig. 5
From: The false alarm: Rosai–Dorfman disease of breast: case report
a Histiocytes with enlarged, round-to-oval hypochromatic nuclei and abundant eosinophilic cytoplasm admixed with lymphocytes and a prominent lymphoid collection (H&E ×400). b Histiocytes engulfing lymphocytes and red blood cells (emperipolesis) (H&E ×400). c CD 68 positivity in the cytoplasm of the histiocytes (IHC ×400). d S100 positivity in the cytoplasm of the histiocytes (IHC ×400)