Cystic Spaces in the Endometrium on Ultrasound and Correlations With Pathological Diagnosis: A Contemporary Retrospective Cohort Study in a Tertiary Centre.

Objectives: To determine the correlation between the ultrasound finding of cystic spaces in the endometrium and endometrial hyperplasia or cancer.

Materials and methods: We performed a retrospective cohort study at a tertiary teaching hospital in Victoria, Australia, between January 2014 and December 2016. Patients who had a tertiary ultrasound where the endometrium was assessed and underwent endometrial sampling in the subsequent year were included.

Results: There were 1614 patients who were included, and 154 (9.5%) had endometrial cystic spaces on ultrasound. Sensitivity, specificity, positive predictive value and negative predictive value for a histological finding of polyps were 16.3%, 93.4%, 51.3% and 72.3%, respectively; for endometrial hyperplasia without atypia (EH no A) 40.7%, 91.0%, 7.1% and 98.9%, respectively; for hyperplasia with atypia (EH with A) 25.0%, 90.8%, 5.2%, 98.4%, respectively and for endometrial cancer were 19.5%, 90.7%, 5.2% and 97.7%, respectively. When adjusted for age, endometrial thickness and the presence of polyps on ultrasound, cystic spaces increased the odds of a histologic diagnosis of polyps (adjusted odds ratio (aOR) 2.13 (95% CI 1.41-3.21) P < 0.001) or EH no A (aOR 5.20 (95% CI 2.06-13.12) P < 0.001) and reduced the odds of endometrial cancer (aOR 0.26 (0.08-0.81) P = 0.02).

Conclusion: Cystic spaces on ultrasound are more likely to indicate the presence of EH no A or an endometrial polyp than endometrial cancer. As one in ten patients who had cystic spaces on tertiary ultrasound had a pathologic diagnosis of EH with A or carcinoma, there remains a need for sampling in this group until better data are available.