Fig. 2

a-b HE morphology of the patient. Tumor cells were irregular sheet-like and nest-like distribution, surrounded by proliferative fibrous stroma. The tumor cells in the nest are small round or oval, with few cytoplasm, unclear cell boundaries, round or oval hyperchromatic nuclei, unclear nucleoli, and mitotic figures were easy to observe (10× and 40×). c-d Desmoplastic small round cell tumor shows immunoreactivity for CD56 (40×) and WT-1 (40×). e Desmoplastic small round cell tumor shows positive Ki-67 with an index of 95% (40×). f Vim stain revealed the characteristic dot-like perinuclear pattern (40×). g Blood smear showed no obvious increase or decrease of white blood cells, normal neutrophils, and middle and late red blood cells account for 6/100 nucleated cells, and platelets were scattered. h Bone marrow smear image. The cancer cells were scattered or clustered. Their cell bodies were large with unclear boundaries and a large amount of cytoplasm, stained with purple-blue or purple-red, partially foamy, with large nuclei and chromatin accumulation. Naked nuclear tumor cells were frequently observed