A hypoechoic deep endometriosis nodule is noted within the hyperechoic uterosacral ligament, infiltrating the parametrium. In this case, the ipsilateral ureter is extrinsically compressed by the nodule, resulting in a hydroureter. This is depicted by the tubular anechoic structure.

Noninvasive ultrasound diagnosis of endometriosis

A hypoechoic deep endometriosis nodule is noted within the hyperechoic uterosacral ligament, infiltrating the parametrium