Figure 4b. Pseudowidening of the endometrium in a 49-year-old woman. (a) Sagittal T2-weighted image shows an ill-defined area of high signal intensity along the posterior myometrium (arrows). The lesion simulates widening of the endometrium but actually represents benign, extensive invasion of ectopic endometrium into the myometrium. (b) Photograph of the histopathologic slide shows ectopic endometrial tissue extensively extending into the myometrium (arrows), an appearance that corresponds to the endometrial pseudowidening on the T2-weighted image. Arrowheads = eutopic endometrium.