The Sonographic Appearance of Endometrial Intraepithelial Neoplasia.

Objectives: To describe the sonographic findings of endometrial intraepithelial neoplasia (EIN), a precursor of endometrial cancer.

Methods: Cases were found by word search of pathology database 1/2013 to 6/2019. One hundred and seventy-eight patients with ultrasound <1 year prior to biopsy were included. Medical records were searched for patient data. Two radiologists blindly classified images. Differences of opinion were decided by clinical report. Univariate and multivariate analyses were performed.

Results: Median time between ultrasound and first sampling procedure was 49 days. Median age was 55 (range 28-85) years. Endometrial thickness ranged from 2 to 90 mm. Mean endometrial thickness was 13 ± 6 mm in the noncancer group and 16 ± 11 mm in the cancer group (P = .02). The endometrium was almost always heterogeneous 175/178 (98%). Cysts were almost always multiple (89/109, 82%) and >1 mm (72/109, 66%). Masses were most often >5 mm (56/105, 55%) and ill-defined (41/105, 39%). Vascularity was present in 93/178 examinations (52%) and always associated with cysts and/or mass. There were 92 cancers, 25 with invasion (including 4 with tumor extension into adenomyosis). In 47 cases, the endometrial-myometrial interface was graded as ill-defined, 39 of whom had hysterectomy. There was macroscopic cancer in 11, microscopic cancer in 4, and invasive carcinoma in 12 patients (P for invasive cancer versus other outcomes = .02). Depth of invasion was 5- >95%, with 6 cancers >50%. Multivariate analysis showed thickness, polyps, and type of bleeding as the best set of independent variables for cancer (area under the receiver operating characteristic (ROC) curve [AUC] = .75). Replacing type of bleeding with age or menopausal status had AUC of .73 and .74, respectively.

Conclusions: EIN has a variety of sonographic appearances with thickened endometrium with cysts and masses being common. Ill-definition of the endometrial-myometrial interface is a poor prognostic finding when seen in the absence of adenomyosis.