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

OBJECTIVES: The primary aim is 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 is to compare our findings with published data on women with AUB.

METHODS: Patients presenting in seven ultrasound centers from 2011 until 2018 for indications unrelated to abnormal vaginal bleeding underwent transvaginal ultrasound examination using the IETA examination technique and measurement technique. The ultrasonography was performed either as part of routine gynecological examination, follow-up of non-endometrial pathology, or in the workup before undergoing treatment for infertility, uterine prolapse or ovarian pathology. Ultrasound findings were described using IETA terminology. Findings were compared to 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: The IETA3 study includes 1745 women without vaginal bleeding 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). 858 women were premenopausal (49%), and 887 women were postmenopausal (51%). Histology showed endometrial cancer (EC) and/or endometrial intraepithelial neoplasia (EIN) in 29 (2%) women, endometrial polyps in 1028 (59%), intracavitary myomas in 66 (4%), proliferative or secretory changes or hyperplasia without atypia in 144 (8%), endometrial atrophy in 265 (15%) and insufficient tissue in 5 (0.3%). Most EC and EIN (25/29; 86%) were diagnosed after menopause. The mean endometrial thickness in women with EC or EIN was 11.2mm (95% confidence interval [CI]: 8.9 to 13.6), which made them on average 2.5mm (95% CI: +0.3 to +4.6) thicker than their benign counterparts. Malignant endometria more frequently manifested non-uniform echogenicity (22/29; 76%) than benign endometria (929/1716; 54%) (difference +21.8%; 95% CI: +4.2 to +39.2). Of EC and EIN, 31% (9/29) showed moderate to abundant vascularization (color score 3-4) compared to 13% (220/1716) of benign outcomes (difference +18.2%; 95%CI: -0.5 to +36.9), and multiple multifocal vessels were recorded in 24% (7/29) versus in 4% (68/1716) (difference +20.2%; 95%CI: +4.6 to +35.7). A regular endometrial-myometrial border was less frequently seen in women with EC and/or EIN (19/29; 66%) vis-à-vis benign outcomes (1412/1716; 82%) (difference 16.8%; -34.2 to +0.6). A single dominant vessel was the most frequent vascular pattern in asymptomatic endometrial polyps (666/1028; 65%). Both in women with and without AUB malignant endometria usually manifested heterogeneous echogenicity, but malignant endometria were on average 8.6mm (95% CI 5.2 to 12) thinner in women without AUB and less intensely vascularized (difference in color score 3-4: 26.8%; 95%CI: 1.3 to 52.2). Asymptomatic endometrial polyps, both in pre- and postmenopausal women, were associated with thinner endometrium, and they more frequently manifested a bright edge, a regular endo-myometrial junction, and a single dominant vessel than polyps in symptomatic women and they were less intensely vascularized.

CONCLUSION: We describe the typical ultrasound features of endometrial cancer, polyps, and other intracavitary histologies using IETA terminology in women without AUB. Our results suggest that asymptomatic polyps and endometrial malignancies may present with thinner and less intensely vascularized endometria than their symptomatic counterparts. This article is protected by copyright. All rights reserved.