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Answer: Ovarian Torsion.

Findings:

  • CT shows a 12.4 x 12.0 x 10 cm complex mass within the pelvis with peripheral cystic structures. Given the history this is suspicious for ovarian neoplasm or torsion.

  • However, the mass is relatively midline and inseparable from the uterus. The bilateral ovaries are not well visualized. Thus, further imaging is necessary.

  • Ultrasound reveals a normal uterus and left adnexal structures. A normal right ovary is not seen.

  • There is a 15.0 x 10.0 x 11.7 cm heterogeneous right adnexal mass, with no flow. There is moderate free fluid in the cul-de-sac.

  • Patient was taken to the OR, where 1080 degrees, or three full 360 degrees, of clockwise torsion of the right ovary had occurred. A right salpingo-oophorectomy was performed.

  • Pathology reported a 14.1 x 12.2 x 6.0 cm intact ovary consisting of diffusely congested ovarian parenchyma, consistent with ovarian torsion.

  • No mass was identified.

Discussion:

  • Ovarian torsion refers to rotation of the ovary on its vascular pedicle. Torsion tends to affect adolescents, possibly due to the changing weight of their adnexae, women in their 20s and postmenopausal women. Approximately 20% of cases of torsion occur during pregnancy, with ovulation induction introducing a major risk factor. A total of 50-80% of all torsion cases are associated with an adnexal mass, usually either a nonneoplastic cyst or benign neoplasm. In infants, children, and adolescents there is usually no underlying mass. Torsion usually presents with severe lower abdominal and pelvic pain, nausea and vomiting.

  • The ovary has a dual arterial and venous blood supply. The arterial supply is derived from the ovarian artery that branches from the abdominal aorta, as well as from the adnexal branches of the uterine artery off the internal iliac. The venous system parallels the arterial, with the exceptions that the left ovarian vein empties into the left renal veinĀ and that the right ovarian vein courses into the inferior vena cava.

  • Ultrasound with Doppler is the imaging modality of choice in the detection of torsion. Ovarian enlargement with peripheral follicles is the most common finding. In addition, there may be irregular echogenic areas within the ovary, corresponding to stromal edema and hemorrhage. On color Doppler, little or no venous flow is present in the ovary. This finding is followed by a lack of intraovarian arterial flow as significant vascular congestion occurs. Likewise, when torsion is complete, no arterial waveforms can be detected within the ovary. A twisted pedicle is a relatively specific sign for ovarian torsion, but is not always present. In the case of intermittent torsion, a hyperemic enlarged ovary may be present. CT scan may demonstrate ovarian enlargement, small or immature peripheral follicles, and intraperitoneal fluid.

  • Treatment consists of laparoscopic uncoiling of the torsed ovary with possible oophoropexy. The recurrence of ovarian torsion is rare, except in cases of profoundly enlarged ovaries, so many believe oophoropexy is unwarranted. Salpingo-oophoretomy is performed if severe vascular compromise is present or if tissue necrosis is clearly evident. However, the size, color, and edema of the ovary may not accurately reflect the amount of tissue injury, so multiple studies now support early conservative management with a success rate of 88% or greater.
Key Points:
  • Approximately 20% of cases of torsion occur during pregnancy, with ovulation induction introducing a major risk factor.

  • 50-80% of all torsion cases are associated with an adnexal mass.

  • The ovary has a dual arterial and venous blood supply.

  • Imaging findings include ovarian enlargement, small or immature peripheral follicles, and intraperitoneal fluid.

  • In the case of intermittent torsion, a hyperemic enlarged ovary may be present.

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