Histological examination of splenic HS. (A) The spleen predominantly showed a diffuse proliferation of medium-sized to large tumor cells having mildly hyperchromatic and pleomorphic nuclei, prominent nucleoli, and abundant eosinophilic or clear cytoplasm, mainly within the sinuses and cords of the red pulp, highlighted by silver impregnation (inset) (H&E stains, Original magnification × 200). (B) On high-power view, these large tumor cells exhibited apparent hemophagocytosis of red blood cells or mononuclear lymphocytes (H&E stains, Original magnification × 400). Hemosiderin pigments within the large cells confirmed erythrophagocytosis by Berlin-blue staining (inset). (C) Vascular invasion of these tumor cells was noted in the trabecular artery, very likely inducing multiple foci of peripheral anemic infarction (H&E stains, Original magnification × 40). This could make a clear contrast by elastica van Gieson (EVG) staining (inset).