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 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.