Ovarian transposition: A diagnostic conundrum in the right iliac fossa

A 51-year-old woman presented with a change in bowel habits and weight loss. Initially, she declined colonoscopy; therefore, a routine CT scan of the abdomen and pelvis was performed. Her medical history included treatment for cervical cancer, which had been managed with surgery and pelvic radiotherapy over a decade ago.

The routine CT scan identified a 30mm cystic lesion in the right iliac fossa, suspected to represent an appendiceal mucinous lesion (Figure 1). The appendix could not be visualised separately, with all other structures appearing normal.

Two weeks later, the patient experienced an acute episode of right iliac fossa pain, necessitating hospital admission. Given the broad range of potential diagnoses, another CT scan was performed. Upon reviewing her surgical history, it was noted that she had previously undergone a radical hysterectomy and ovarian transposition (Figures 2a and 2b).

Following this, the patient experienced another bout of severe right iliac fossa pain two weeks later, prompting suspicion of involvement of the transposed ovaries. For this reason, an ultrasound was conducted, revealing an avascular cyst with a small volume of adjacent free fluid. Despite this, no “swirl sign” indicative of a twisted vascular pedicle was observed (Figure 3). Subsequently, an MRI was conducted, revealing a simple cyst in the right transposed ovary without evidence of torsion but indicating mild caecal colitis (Figures 4a and 4b).

Ovarian transposition, also referred to as oophoropexy, is a widely practised surgical procedure primarily performed in premenstrual women undergoing pelvic radiation therapy for cancer with either vaginal brachytherapy or external beam radiation [1,2]. The importance of this is to preserve ovarian function and fertility by relocating the ovaries outside of the radiation field, thereby reducing the ovarian dose to 5–10% compared to a non-transposed ovary [3]. An extensive literature search indicates a successful preservation rate of around 70% for ovarian function in premenopausal women who have previously undergone an ovarian transposition and subsequently received pelvic radiation for cancer [8].

Ovarian transposition is frequently performed at the time of hysterectomy in cervical cancer patients below the age of 40–45 years old during the early stages of the disease. This strategic timing helps to avoid additional surgical interventions following staging [2,4]. Consequently, radiation therapy can be carried out in the future if indicated, as the radiosensitive ovaries have already been safeguarded by this relocation procedure. Additionally, multiple surgical techniques for ovarian torsion in conjugation with radical hysterectomy have been documented, including laparotomy, laparoscopy, a mixed transvaginal laparoscopic approach, and robotic-assisted procedures [5,6]. During the procedures, the ovaries and vascular pedicle are separated from their ligamentous attachment to the uterus, mesovarium and pelvic sidewall, and affixed to the lateral abdominal wall at the pelvic brim [7].

Despite its benefits, ovarian transposition is not without risks. The most common complications include ovarian failure (with or without radiation), cyst development, and ovarian metastases [8]. Thus, it serves as an imperative asset in preserving fertility and ovarian function in the context of radiation therapy. For this reason, careful consideration of potential complications is vital during clinical decision-making.

Moreover, recognising the significance of identifying ovarian tissue post-transposition is paramount in this case. An essential imaging feature is the presence of a vascular pedicle that can be traced back to the gonadal arteries connecting to major vessels such as the aorta, inferior vena cava, or renal veins. Additionally, transposed ovaries are susceptible to a spectrum of pathologies similar to those affecting the pelvic ovaries, including torsion, benign and malignant cysts and tumours [4]. As illustrated in this case, the differential diagnosis of a cystic lesion within the right iliac fossa is extensive, highlighting the dependence on clinical presentation and prior medical history for accurate diagnosis. Potential diagnoses include benign or malignant appendiceal tumours, Meckel’s diverticulum, appendix abscess, diverticular abscess, psoas abscess, Crohn’s abscess, postoperative collections, and ovarian cysts [9–11]. Furthermore, clinicians should consider the prospect of ovarian cysts and necrotic cystic lesions secondary to ovarian torsion, as their presentation differs in transposed ovaries [11].

In conclusion, this case clearly illustrates the significance of attaining a comprehensive clinical history, utilising diagnostic imaging, and fostering multidisciplinary collaboration. These components are essential in achieving an accurate diagnosis when encountering a complex cystic lesion involving transposed ovaries.