Ovarian pseudotorsion: pelvic adhesions as an unusual cause of ovarian infarction

A 30-year-old female with a thirteen-year history of end-stage renal disease on peritoneal dialysis presented to the emergency department with acute onset left lower quadrant abdominal pain that morning. She denied fever, chills, nausea, vomiting, or diarrhoea. Physical examination revealed tenderness to deep palpation of the left adnexa without a palpable mass. Urine pregnancy test was negative and a complete blood count was unremarkable.

Transabdominal and endovaginal ultrasound with Doppler was performed to assess for ovarian torsion. Sonographic images revealed an enlarged and heterogeneous left ovary with peripheral colour Doppler flow and a lack of internal colour Doppler flow or arterial and venous waveforms (Figure 1-3).

Background:

Ovarian infarction is commonly the result of untreated ovarian torsion. The ovaries receive blood supply from the ovarian and uterine arteries. The ovarian artery runs in the suspensory ligament of the ovary, also known as the infundibulopelvic ligament, while the uterine artery and its branches run through the broad ligament [1]. When either of those ligaments become twisted upon themselves, venous congestion, oedema, compression of the arteries, and loss of blood supply to the ovary will sequentially occur. While approximately 50% of women diagnosed with ovarian torsion have no ovarian pathology, there are many risk factors for ovarian torsion, the most common being an ovarian cyst or mass 5 cm or larger [6]. In this case, the patient had an enlarged left ovary with cystic reticulations measuring up to 6.2 cm (Figure 1,2).

Clinical Perspective:

Differential diagnoses for acute unilateral pelvic pain in premenopausal patients include non-gynaecological pathologies such as appendicitis or diverticulitis, as well as gynaecological pathologies such as ectopic pregnancy, ruptured ovarian cyst, tubo-ovarian abscess, and ovarian torsion.  Serum or urine beta-hCG and complete blood count should be obtained to assist in diagnosis. Therefore, ovarian torsion needs emergent surgical treatment to prevent further ischemia and subsequent infarction [5]. In a 10-year case review in a women’s hospital, ovarian torsion was found to be the fifth-most common cause for emergent surgical intervention in women [6].

Imaging Perspective:

Pelvic ultrasound with colour and spectral Doppler is the modality of choice in the investigation of suspected ovarian torsion and other gynaecological emergencies, with both transabdominal and transvaginal images being of use. Findings suspicious for ovarian torsion include an asymmetrically enlarged, edematous ovary with diminished or absent flow on colour and spectral Doppler [1,2]. Ancillary imaging findings include free pelvic fluid and an underlying cystic or solid lesion of the ovary [1]. Occasionally, a “whirlpool” sign may be seen, which may represent twisting of the infundibulopelvic ligament and vascular pedicle of the ovary [3,4]. This finding in and of itself is not diagnostic of ovarian torsion, as other more sensitive imaging findings of diminished ovarian flow and oedema must be present. Complete absence of vascularity in the form of colour and spectral Doppler flow indicates necrosis has already occurred, however, this is not required to diagnose ovarian torsion [1]. In the above-described patient, there was scant peripheral colour flow along the anterior border (Figure 2A) and no discernable arterial or venous waveforms (Figure 3).

Outcome:

Surgical detorsion is the treatment of choice, and direct visualization of rotated ovary during surgery is the definitive diagnosis for ovarian torsion. However, in patients with prolonged torsion and resultant ovarian infarction, an oophorectomy is the treatment of choice [1,4]. Additionally, patients with newly-discovered solid or suspicious masses will undergo oophorectomy rather than detorsion for pathological analysis. Patients with large cystic lesions may undergo ipsilateral oophorectomy to prevent further torsion and potential subsequent infarction.

Take-Home Message/Teaching Points:

The patient described in this case underwent diagnostic laparoscopy during which left ovarian infarction without actual torsion was identified. Instead, there were dense adhesions seen throughout her lower abdomen and pelvis (Figure 4), for which general surgery was called to the operating room to perform lysis of adhesions to free the left ovary and uterus. The patient had a long history of peritoneal dialysis; therefore, this unfortunate sequela is likely from the formation of adhesions. The compression of the arteries by adhesions and immobility of the ovary was the most likely cause of loss of blood supply. Thus, we identify this case as ovarian infarction secondary to extrinsic compression. Sonographically, it is identical in appearance and indistinguishable from true ovarian torsion. Radiologists and clinicians should be aware of less common causes of ovarian infarction, or “pseudotorsion”, including adhesions and large or aggressive space-occupying ovarian or extra-ovarian lesions, to better guide patient care and further management.