Abstract Background The accurate cytological diagnosis of endometrial carcinomas by minimally invasive method has a broad application. There
Abstract Background The accurate cytological diagnosis of endometrial carcinomas by minimally invasive method has a broad application. There are several articles described the morphological characteristics but not arrangements of endometrial lesion cells on LBC slides. Methods A retrospective study was conducted using 175 endometrial samples obtained by direct negative pressure suction with disposable endometrial sampler. All lesions were diagnosed both cytologically and histologically, and the diagnostic results were compared and analyzed. Results The cytological diagnoses of polyps, simple or complex hyperplasia, and atypical hyperplasia were highly consistent with the histological diagnosis. The cytological features of polyps and normal endometrium, as well as simple and complex hyperplasia, are the same. Among 82 cases of histologically confirmed adenocarcinoma, the cytological diagnosis were adenocarcinoma cells (46 cases, 56.10%), suspected for adenocarcinoma cells (22 cases, 26.83%), and false negative (14 cases,17.07%). Retrospective reviewing the slide suggest diagnostic parameters such as significantly enlarged nuclei, multistage papillary arrangements, large and numerous nucleoli, and large vacuoles containing neutrophils in the cytoplasm are reliable diagnostic criteria for endometrial carcinoma cells; on the other hand, ignorance of lobulated arrangements and escaped arrangements are the main reasons for missed diagnosis. Conclusions The cytological diagnosis of endometrial lesions not only depends on the morphological characteristics of cells, but also need careful observations of the cellular arrangements.