Fig. 1

Pregnant women presented with untypical pelvic pain and pressure showing a hypoechoic parauterine mass at B-Mode sonography measuring 39 mm (A). Positional relation to the uterine artery (B) and intralesional flow at color-coded sonography with pw-Doppler curves non typical for uterine vessels and typical yin-yang sign for an aneurysmatic lesion (C). Clarification of diagnosis suspect for UAA using contrast enhanced MRI (D-F). Contrast enhanced QUISS-sequence showing intra-aneurysmatic collection of contrast agent (E, arrow) comparing to native T1w-sequence (D, arrow). MR angiography shows the exact anatomy of the internal iliac artery with the true aneurysm originating from the uterine artery (F, arrow). Control MRI before the calculated date of birth showed a significant decreased and still occluded aneurysm (G, arrow)