A case of uterine torsion concurrent with a ruptured ovarian endometrial cyst

The patient was a 54-year-old female presented with severe abdominal swelling and intermittent pain. On emergent CT, massive ascites with thickened peritoneum and intra-pelvic cystic mass approximately 20 cm in diameter were observed. The cyst wall showed redundant irregular shape. The uterus was enlarged with intramural mass located at its right anterior fundus. MRI showed this pelvic cyst as high intensity on T1-weighted images, so that it was suspected as an endometrial cyst. The operation revealed the rupture of endometrial cyst and the uterine torsion of 180° around the long axis. Retrospectively, the X-shaped configuration of the upper vagina was observed on MRI and both the adnexa, including right ovarian cyst, were connected to the opposite side ovarian vein. Torsion of a non-gravid uterus is rare. In this case, the uterine torsion seemed to be caused by enlarged uterine body and ruptured endometrial cyst. Radiologists should be aware of this potential complication of huge ovarian mass and enlarged uterus and its appearance.