Ultrasound features of endometrial pathology in women without abnormal uterine bleeding: results from the International Endometrial Tumor Analysis Study (IETA3)

OBJECTIVES: The primary aim of this study was to describe the ultrasound features of various endometrial and other intracavitary pathologies in women without abnormal uterine bleeding (AUB) using the International Endometrial Tumor Analysis (IETA) terminology. The secondary aim was to compare our findings with published data on women with AUB. METHODS: This was a prospective observational study of women presenting at one of seven centers specialized in gynecological ultrasonography, from 2011 until 2018, for indications unrelated to AUB. All patients underwent transvaginal ultrasound using the IETA examination and measurement techniques. Ultrasonography was performed as part of routine gynecological examination or follow-up of non-endometrial pathology, or as part of the work-up before undergoing treatment for infertility, uterine prolapse or ovarian pathology. Ultrasound findings were described using the IETA terminology. Endometrial sampling was performed after the ultrasound scan. The histological endpoints were endometrial atrophy, proliferative or secretory endometrium, endometrial hyperplasia without atypia, endometrial polyp, intracavitary leiomyoma, endometrial intraepithelial neoplasia (EIN), endometrial cancer (EC) and insufficient tissue. The findings in our cohort of women without AUB were compared with those in a published cohort of women with AUB who were examined with transvaginal ultrasound between 2012 and 2015 using the same IETA examination technique and terminology. RESULTS: In this study (IETA3), we included 1745 women without AUB who underwent a standardized transvaginal ultrasound examination followed by either endometrial sampling with histological diagnosis (n = 1537) or at least 1 year of clinical and ultrasound follow-up (n = 208). Of these, 858 (49.2%) women were premenopausal and 887 (50.8%) were postmenopausal. Histology showed the presence of EC and/or EIN in 29 (1.7%) women, endometrial polyps in 1028 (58.9%), intracavitary myomas in 66 (3.8%), proliferative or secretory changes or hyperplasia without atypia in 144 (8.3%), endometrial atrophy in 265 (15.2%) and insufficient tissue in five (0.3%). Most cases of EC or EIN (25/29 (86.2%)) were diagnosed after menopause. The mean endometrial thickness in women with EC or EIN was 11.2 mm (95% CI, 8.9-13.6 mm), being on average 2.4 mm (95% CI, 0.3-4.6 mm) thicker than their benign counterparts. Women with malignant endometrial pathology manifested more frequently non-uniform echogenicity (22/29 (75.9%)) than did those with benign endometrial pathology (929/1716 (54.1%)) (difference, +21.8% (95% CI, +4.2% to +39.2%)). Moderate to abundant vascularization (color score 3-4) was seen in 31.0% (9/29) of cases with EC or EIN compared with 12.8% (220/1716) of those with a benign outcome (difference, +18.2% (95% CI, -0.5% to +36.9%)). Multiple multifocal vessels were recorded in 24.1% (7/29) women with EC or EIN vs 4.0% (68/1716) of those with a benign outcome (difference, +20.2% (95% CI, +4.6% to +35.7%)). A regular endometrial-myometrial junction was seen less frequently in women with EC or EIN (19/29 (65.5%)) vs those with a benign outcome (1412/1716 (82.3%)) (difference, -16.8% (95% CI, -34.2% to +0.6%)). In women with endometrial polyps without AUB, a single dominant vessel was the most frequent vascular pattern (666/1028 (64.8%)). In women with EC, both in those with and those without AUB, the endometrium usually manifested heterogeneous echogenicity, but the endometrium was on average 8.6 mm (95% CI, 5.2-12.0 mm) thinner and less intensely vascularized (color score 3-4: difference, -26.8% (95% CI, -52.2% to -1.3%)) in women without compared to those with AUB. In both pre- and postmenopausal women, asymptomatic endometrial polyps were associated with a thinner endometrium, and they manifested more frequently a bright edge, a regular endometrial-myometrial junction and a single dominant vessel than did polyps in symptomatic women, and they were less intensely vascularized. CONCLUSIONS: We describe the typical ultrasound features of EC, polyps and other intracavitary histologies using IETA terminology in women without AUB. Our findings suggest that the presence of asymptomatic polyps or endometrial malignancy may be accompanied by thinner and less intensely vascularized endometria than their symptomatic counterparts.