Fig. 2

Pathological examination of the surgical specimen. HE staining (a and b) indicated that the tumor was composed of a population of small round cells arranged in sheet. Immunohistochemical staining was positive for c CD99, d CD56, e syn and f Ki67 (50%) and negative for g S100. Magnification details: a × 100; b × 200; c × 100; d × 100; e × 200; f × 100; g × 100. g EWSR1 gene translocation was detected by fluorescence in situ hybridization testing (FISH)