Cytological and Histological Diagnosis
According to menstrual cycle, the physiologic endometria were divided into menstrual, proliferative and secretory ones (26).The endometrial lesions mainly includes different types of hyperplasia and cancer (27). Therefore, in this study, according to the endometrial histopathological classification standard established by World Health Organization in 2014 (28) and the Endometrial Cytology Beijing System updated in 2016 (29), the histology of endometria were divided into eight categories: proliferative endometria, secretory endometria, atrophic endometria, endometrial polyps, simple hyperplasia, complex hyperplasia, atypical hyperplasia, and endometrial cancer. The cytological diagnoses were divided into seven categories: proliferative endometrial cells, secretory endometrial cells, atrophic endometrial cells, simple hyperplasia endometrial cells, complex hyperplasia endometrial cells, atypical hyperplasia endometrial cells, and endometrial cancer cells (30). The atypical hyperplasia and endometrial cancer were regarded as positive results.
The sections were divided into satisfactory and unsatisfactory samples (27, 31). The cytological sections of H-E and Papanicolaou stain were all evaluated by optical microscope from two pathologists using the semi-quantitative scoring system, including the cellularity, background blood debris, informative background, monolayer, cell architecture, nuclear details, and cytoplasmic details. Every item was graded from zero to three. The specimen would be reviewed blindly again when there was a disagreement. The highest proportion of results was identified as final (32).