Uterine Ewing sarcoma:a clinicopathological analysis of six cases and review of literature

ZHANG Qiu-ying; ZHANG Rong-jun; HUANG Hai-jian

doi:10.3969/j.issn.1007-8096.2025.02.004

Abstract：Objective To investigate the clinicopathological features of uterine Ewing sarcoma(ES)and to systematically review the literature.Methods The pathological data,follow-up,treatment and prognosis of 6 cases of uterine ES were collected and analyzed with review of the literature.Results The age was 14～67 years old(median 52 years and average 43.5 years).The maximum diameter of the tumor was 2.5～13 cm(average 7.6 cm,median 6.5 cm).Pathologically,it was a undifferentiated small round cell tumor with diffuse growth pattern;tumor cells had less cytoplasm,with uniform size of nuclei and detailed chromatin;small nucleoli were noted,and pathological mitotic figures were frequently found.Some tumor cells were in nest-like arrangement,and Homer-Wright rosettes were seen,consistent with the classic Ewing sarcoma(4/6).In other two cases,tumor cells were epithelioid,or short spindle-shaped,with transparent cytoplasm,vacuole-like nuclei and prominent nucleoli;mitotic figures were frequently noted,with focal necrosis and interstitial thick-walled small blood vessels,which were consistent with non-classical Ewing sarcoma(2/6).Immunohistochemically,tumor cells were positive for CD99(6/6,membrane),Fli-1(6/6),NKX2.2(6/6),SMARCA4(6/6),and Ki67 proliferation index was 30-80％.Genetic testing showed FLI-1-EWSR1 fusion(4/4)and EWSR1 broken-apart(2/2).Conclusion The diagnosis of uterine ES depends on clinical pathology,immunophenotyping and genetic testing,and it needs to be distinguished from other uterine tumors.Due to the rarity of uterine ES,no standard treatment plan has been formulated.