According to NCCN and German guidelines, and as demonstrated in the present case, the diagnosis of LG-ESS is confirmed through histopathological evaluation showing characteristic spindle-cell proliferation with myometrial and/or lymphovascular invasion, supported by immunohistochemical positivity for CD10, estrogen receptor (ER), and progesterone receptor (PR) (Abu-Rustum et al., 2021, Denschlag et al., 2022). This evidence concerns the gene ESR1 and endometrioid stromal sarcoma.