Unusual case of a leiomyoma in the space of Retzius mimicking broad ligament fibroid

Abstract

This case report will discuss an interesting case of a patient who presented with pain in the lower abdomen of 2-month duration. Clinical examination and imaging findings were suggestive of a broad ligament fibroid. However, intraoperatively, the mass was found to be present in the space of Retzius, which is an extremely rare location for such a pathology. The access to the tumour was very challenging. Successful surgical excision was done with the help of a multidisciplinary team involving a gynaecologist, a urologist and an anaesthetist. Histopathology reported it to be benign leiomyoma. Postoperatively, the patient made an uneventful recovery.

Background

Leiomyomas are the most frequent, benign, mesenchymal tumours of female reproductive tract. Although uterus is the most common site, they can develop at any extrauterine location where smooth muscle cells are present.^{1 2} Extrauterine leiomyomas are extremely rare, posing a great diagnostic and surgical challenge due to their unusual occurrence. These rare sites include vulva, ovaries, urinary bladder, urethra and space of Retzius. The space of Retzius is a space between the symphysis pubis and urinary bladder and is a part of extraperitoneal space. The prevalence of leiomyomas in the extraperitoneal space is reported to be around 1.2% only.^{3 4} Majority of the patients remain asymptomatic or present with urinary/voiding problems. However, occasionally, they may present with vague symptoms like pelvic pain or vaginal bleeding. To the best of our knowledge, only seven cases of leiomyoma in the space of Retzius have been reported in the literature so far.⁴ We report this case due to its rare location and atypical presentation. Correct diagnosis and appropriate management involving a multidisciplinary team are crucial for such patients.

Case presentation

A woman in her 30s, para 2, live 2, presented to our gynaecology outpatient department with a chief report of pain in the lower abdomen of 2-month duration, which was insidious in onset and progressive in nature. The pain was not relieved on medications. She reported normal menstrual cycles. Her medical history was unremarkable. Her social and family history was not significant. On general physical examination, she was moderately built and well nourished. An abdomen examination revealed no tenderness or any palpable mass. On local examination, the uterus was anteverted almost 8 weeks in size, and a fixed firm, non-tender mass was felt in the anterior fornix, separate from the uterus. Bilateral fornices were free.

Investigations

Pelvic ultrasound showed a normal uterus with normal endometrial thickness. A complex left adnexal mass of 7×8.6 cm in diameter was present suggestive of a left-sided broad ligament fibroid. Right adnexa were normal. On further evaluation, contrast-enhanced CT (CECT) depicted a large heterodense enhancing mass lesion in the pelvis on the left side measuring 8.4×8.5 cm. There were well-maintained fat planes with urinary bladder and uterus. Inferiorly, the mass was reaching in the prevesical space. There were few tiny foci of calcification noted within the mass. Uterus and both adnexa were separate from the mass and were normal. A provisional diagnosis of left-sided broad ligament fibroid or pedunculated subserosal fibroid was made on CECT. There was also an incidental finding of a calculus of 1.4 cm in the left upper ureter resulting in mild to moderate left-sided proximal hydroureteronephrosis (figure 1). All other haematological and biochemical investigations were normal.

Figure 1.

Gross specimen of leiomyoma in the space of Retzius.

Differential diagnosis

The differential diagnoses for a mass in the space of Retzius include true tumours or similar lesions like an abscess or haematoma, granuloma, haemangiopericytoma, lymphangioma, neurinoma, subpubic cartilaginous cyst and very occasionally leiomyoma and leiomyosarcoma.^{5 6} The case was misdiagnosed preoperatively due to the extremely unusual location of the lesion and atypical presentation.

Treatment

After taking informed written consent and complete preoperative evaluation, the patient was planned for exploratory laparotomy. Intraoperatively, the uterus and bilateral adnexa were normal. A solid mass of approximately 12×12 cm was seen in the prevesical space on the left anterolateral aspect of the urinary bladder. Inferomedially, the mass was reaching up to the bladder neck. Owing to the close proximity of the mass to the bladder, the surgical input of the urologist was required. The mass was adherent to the surrounding tissue and dense vascularity was seen around the mass. Adhesiolysis was done to remove the mass en-bloc and vessels were ligated using a hand-held vessel-sealing device. Complete haemostasis was ensured. The bladder integrity was confirmed by retrograde filling with methylene blue dye diluted with normal saline. Lastly, the abdominal drain (24 French) was placed after excision of the mass. The whole excised mass was sent for histopathology examination. Her postoperative period was uneventful with minimal serosanguineous discharge in the abdominal drain until the second day of surgery, which was then removed on day 3 as its output was nil, and she was discharged after 3 days. The final histopathological diagnosis revealed spindle cell lesion suggestive of leiomyoma (figure 2).

Figure 2.

Axial section of contrast-enhanced CT film showing a space-occupying lesion in the pelvis and its relation to adjacent structures.

Outcome and follow-up

On follow-up visits at 2 weeks, 6 weeks and 3 months, the patient was relieved of her symptoms and able to resume her routine household work.

Discussion

The space of Retzius is a part of extraperitoneal space between transversalis fascia of the abdominal wall and the parietal peritoneum. Leiomyomas in this space are extremely uncommon.^{5 7 8} Various theories have been postulated in the literature owing to their occurrence in this unusual location. It was observed that 83% of the fibroids located extraperitoneally were found in those who had undergone myomectomies via laparoscopic morcellation.⁹ Another possibility could be the origin from the Mullerian or Wolffian duct remnants or smooth muscle cells of vessels.^{10 11} Only a few cases of leiomyomas in the space of Retzius have been reported in the literature so far4–6 10 12 13 (table 1).

Table 1.

Summary of reported cases of leiomyomas in the space of Retzius

Reported by	Year	Age (years)	Presenting symptoms	Imaging
Stutterecker et al10	2001	50s	Case 1: voiding difficulties but no frequency or urgency	Case 1: MRI—5 cm mass anterior to bladder and urethra in pubovesical space
		50s	Case 2: asymptomatic	Case 2: USG—heterogeneous echogenicity mass
Reisenauer et al13	2006	50s	Voiding difficulties	USG—4×3 cm mass between bladder neck and symphysis
Pepe et al12	2013	40s	Bladder voiding symptoms	USG—10 cm diameter mass in anterior zone of the uterus
Niwa et al4	2013	50s	Microscopic haematuria on routine examination	TVS—50×18 mm mass anterior to bladder MRI—94×53×74 mm smooth mass
Sikora-Szczęśniak6	2017	50s	Heavy menstrual bleeding with anaemia	USG—10 cm diameter leiomyoma in anterior wall of uterus
Shweta et al5	2020	20s	Primary infertility Bladder voiding symptoms	USG—59 mm subserosal fibroid in anterior cervical region with simple cyst 86×50 mm in right adnexa CT of the pelvis—7.5×8.6 cm solid-enhancing lesion anterior to vagina and inferior to urinary bladder

TVS, transvaginal sonography; USG, ultrasonography.

In the case described here, as the tumour had no attachment to the bladder or uterus and there was no history of any surgery in the past, we assume that it probably originated from the smooth musculature of the vessels present in the space of Retzius or from the mesenchymal stem cells. Most patients present with severe voiding difficulty as previously reported, but our patient presented with pain in the lower abdomen only, which made the correct diagnosis even more challenging. Ultrasonography (USG) is the first line of investigation followed by MRI or CT scan. In our patient, imaging studies (USG and CECT) pointed towards the diagnosis of a broad ligament fibroid and it was only intraoperatively that the accurate diagnosis was made. The definitive management of extraperitoneal leiomyomas involves total excision of the tumour via abdominal or vaginal approach with a multidisciplinary team involving a gynaecologist, a urologist and an anaesthetist to avoid any injury to the bladder and urethra.¹⁰

Patient’s perspective.

I had pain lower abdomen for which I went to gynecologist for examination and was diagnosed with a tumor of uterus. I was really very shocked on knowing this and it was cancer which first came to my thoughts. I was terrified on thinking about my illness. For how many days I'll survive. The thought of my kids without me would just make me cry. My doctors explained me about my disease and counselled me in my time of need.

On the advice of my doctors, I decided to go for laparotomy after thorough evaluation. On the day of surgery, I was anxious but everything went well. After surgery, we came to know that it was not uterine tumor and with God’s grace my uterus was saved. It was a pelvic mass near bladder and uterus. With the support of all medical team and my family, I had a fast recovery and my pathology came to be benign on final report. I was so relieved and happy.

Learning points.

• The occurrence of leiomyomas in extraperitoneal space is extremely rare.

• Clinical examination and imaging can miss the correct diagnosis of the patient.

• A multidisciplinary approach in the management of such patients is crucial for an optimised surgical outcome.

Ethics statements

Patient consent for publication

Obtained.