The presence of one or more endoscopic findings of endometrial focal hyperemia/strawberry aspect, micropolyposis, and/or stromal edema was regarded as hysteroscopic CE, whereas the infiltration of ≥5 CD138(+) ESPCs in 1 HPF (= ≥50 CD138(+) ESPCs in 10 HPFs) was defined as histopathologic CE in this study. This evidence concerns the gene SDC1 and cholesteryl ester measurement.