Uterine torsion in the second trimester of pregnancy with a large leiomyoma identified in a cesarean section for abruptio placentae : a case report and literature review

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Introduction
Leiomyoma is one of the most common complications in pregnant women.The major symptoms caused by leiomyoma in a pregnant uterus are localized pain, fever, and nausea.However, unexpected and unpredicted complications can also occur.Here, the authors present a case of a pregnant woman at 23 weeks of gestation who presented with abruptio placentae and torsion of the uterus with a large leiomyoma.

Case Report
A 28-year-old pregnant with 0 gravida was diagnosed with a leiomyoma approximately 15 cm in size in the right-anterior uterine wall (Figure 1A).She was followed up in the hospital from 7+3 weeks of gestation.The patient visited the emergency room at 23+0 weeks of gestation because of an increase in vaginal discharge.A physical examination revealed obvious preterm premature rupture of membranes (pPROM), abnormal vaginal bleeding, and a bulging water mass approximately 6 cm into the vagina.
Transvaginal and abdominal sonography identified a high echoic 8-cm mass considered a hemorrhage behind the placenta and limited amniotic fluid volume.The fetal heart rate monitoring showed frequent severe and variable deceleration to under 70 bpm.Because the authors diagnosed the patient with abruptio placenta with fetal non-reassuring status, an emergency cesarean section was performed.The operative findings showed a uterus that was obviously enlarged by both the fetus and leiomyoma, making it difficult to identify the specific anatomical orientation.
After an incision was made in the uterine wall, the male fetus was delivered.After the delivery, the placenta was removed from the uterus, and a hemorrhage of approximately 5 cm was observed in the side of the uterus, indicating evidence of abruptio placentae (Figure 1B).After the uterine incision was sutured, it was determine that uterus was rotated 150 degrees in a clockwise direction (Figure 1C).Therefore, the uterine incision had unfortunately been performed in the backside of the uterine wall.Her postoperative course was good and she was discharged on post-operative day 6.At six months after delivery, the authors performed a myomectomy (Figure 1D).

Discussion
Uterine torsion is defined as a rotation of more than 45 degrees, and 62% of all affected cases are rotated in a clockwise direction.The frequency of uterine torsion in a pregnancy is 6% in the first trimester, 26% in the second trimester, and 67% in the third trimester 1) [1].
In the present case, the uterine rotation was in a clockwise direction and occurred during the second trimester.Because a torsion event is considered to result from an increased uterine size, the existence of a leiomyoma may have promoted uterine torsion in this case.Although few reports have been published regarding uterine torsion in pregnant women complicated by leiomyoma [2][3][4], the eti-ology of the events in this case can be explained by the leiomyoma.
The uterus might first have been rotated by the leiomyoma, and the internal pressure of the uterus may then have increased.As a result, pPROM and abruptio placentae occurred.Furthermore, another possibility should also be considered.Acute amniotic fluid loss followed by abruptio placentae might cause a rapid shrinkage in uterine volume followed by uterine torsion caused by the imbalanced condition resulting from the presence of a large leiomyoma.It is difficult to retrospectively identify the specific etiology in these cases.Achieving an accurate diagnosis of uterine torsion in an emergency situation is even more difficult.
If the torsion occurred slowly as a chronic event without any symptoms, the time course of the movements that occurred during uterine movements could be traced by the observation of the partial calcification of the placenta on ultrasound or X-ray.In these cases, under careful observation, a term delivery might be possible [5].However, most affected cases, including the present, are sudden onset and require a cesarean section to rescue both the mother and the fetus.In fact, most cases of uterine torsion are diagnosed by cesarean section [6], fetal mortality of up to 12%, and occasional maternal mortality have been reported in pregnant women [7].Because the major symptoms of uterine torsion are, in most cases, abdominal pain, nausea, vomit-ing, abnormal genital bleeding, and shock status [8], focusing on risk factors, such as uterine malformation, adhesion in the pelvis, ovarian cysts, a horizontal position of the fetus, as well as the presence of a leiomyoma, may help to pre-acknowledge and achieve an early diagnosis of uterine torsion.

Conclusions
Here, the authors report a case of abruptio placentae with uterine torsion in the second trimester of pregnancy with a large leiomyoma.Their experience in this case suggests that it is important to consider the potential risk of uterine torsion in pregnancy when indicated, especially in cases at risk of having a large leiomyoma.