Torsed retroperitoneal leiomyomas: A case report and review of literature

Abstract

BACKGROUND

Retroperitoneal leiomyomas (RLs) are rare benign tumours that can occur in the pelvic and/or abdominal parietal retroperitoneum. Once torsion occurs, it causes acute abdominal pain and can even lead to serious consequences such as gangrene, peritonitis, haemoperitoneum and shock if not identified and treated promptly. Therefore, a better understanding of the characteristics of RL torsion is needed. Here, we present a case of acute pedicle torsion of an RL in the posterior peritoneum followed by a literature review.

CASE SUMMARY

Herein, we report the case of a 42-year-old woman with RL torsion. The patient visited our hospital complaining of lower abdominal pain for 6 d. Pelvic examination revealed a tender mass superior to the uterus. Pelvic MRI revealed an anterior uterine mass, multiple uterine fibroids and slight pelvic effusion. MRI suggested the possibility of a subserosal myoma of the anterior uterine wall with degeneration. Intraoperative exploration revealed a 10 cm pedunculated mass arising from the posterior peritoneum, with the pedicle torsed two times. Pathological examination confirmed a torsed RL.

CONCLUSION

In the case of a pelvic mass complicated with acute abdomen, the possibility of torsion should be considered.

Key Words: Leiomyoma, Retroperitoneum, Torsion, Abdominal pain, Case report

Core Tip: Retroperitoneal leiomyoma torsion is extremely rare. We report a case of acute pedicular torsion of a leiomyoma in the posterior peritoneum, followed by a literature review. The review suggested that RL torsion mainly occurs in female patients, and the most prominent clinical symptom is abdominal pain. The possible imaging features of torsed retroperitoneal leiomyomas include a well-circumscribed mass separate from the uterus and adnexa, no enhancement, a torsed pedicle, and ascites. If the diagnosis is unclear, surgical exploration should be considered to confirm the diagnosis in a timely manner to reduce the risk of other complications.

INTRODUCTION

Retroperitoneal leiomyomas (RLs) are rare benign tumours that can occur in the pelvic and/or abdominal parietal retroperitoneum. These tumours are characterized by smooth muscle differentiation and can be primary lesions or metastases from other sources[1]. Because of their rarity and uneventful clinical course, limited information is available about RLs.

RL torsion is extremely rare; once torsion occurs, it can cause acute abdominal pain and even lead to serious consequences, such as gangrene, peritonitis, haemoperitoneum and shock, if not identified and treated promptly[2-5]. Therefore, a better understanding of the characteristics of RL torsion is needed. Here, we present a case of acute pedicle torsion of an RL in the posterior peritoneum, followed by a literature review.

CASE PRESENTATION

Chief complaints

A 42-year-old woman (gravida 1, para 1) visited our hospital complaining of lower abdominal pain that started 6 d prior.

History of present illness

The patient came to our hospital complaining of severe, sudden-onset and constant dysmenorrhea-like pain localized to the lower abdomen 6 d prior. Her pain occurred while she was doing housework and was associated with loss of appetite but was not accompanied with fever, nausea, vomiting, or diarrhoea. The pain had nothing to do with food or body position. After 5 d of oral cefuroxime anti-inflammatory treatment, the pain gradually decreased, but there was still dull pain in the lower abdomen with no other discomfort.

History of past illness

She was first diagnosed with fibroids 6 years prior and underwent a Caesarean section 17 years prior and right mammary fibroma resection 1 year prior.

Personal and family history

The patient denied having any relevant family history.

Physical examination

Her body temperature was normal. Pelvic examination revealed a tender mass superior to the uterus that was well circumscribed, medium in texture and approximately 10 cm × 10 cm × 10 cm in size.

Laboratory examinations

The level of oncologic marker antigen 125 was 48.7 U/L, which was slightly greater than normal. No other abnormalities were found in routine blood analyses.

Imaging examinations

Ultrasonography revealed a hypoechoic mass in front of the uterus. Pelvic magnetic resonance imaging (MRI) revealed an anterior uterine mass, multiple uterine fibroids and slight pelvic effusion (Figure 1). No other pelvic abnormalities were found. MRI suggested the possibility of a subserosal myoma of the anterior uterine wall with degeneration.

Figure 1  Pelvic magnetic resonance imaging showing an anterior uterine mass, multiple uterine fibroids and slight pelvic effusion.

FINAL DIAGNOSIS

The final diagnosis was RL torsion.

TREATMENT

Based on her symptoms and age and the size of the mass, exploratory laparoscopy was performed. Intraoperative exploration revealed that part of the greater omentum was adhered to the anterior abdominal wall, and a large pedicled mass was observed in the pelvic cavity in front of the uterus, surrounded by and loosely adhered to the small intestine. The mass was 10 cm × 10 cm × 10 cm in size, greyish-red in colour, smooth on the surface and of medium quality (Figure 2). The pedicle was located 2 cm from the posterior peritoneum to the left of the rectum and was torsed 2 times (Figure 3). The upper and lower abdomens were explored, and no abdominal masses or enlarged lymph nodes were found. Pathological examination confirmed a retroperitoneal leiomyoma with a large area of haemorrhage and infarction. Immunohistochemical tests revealed positivity for desmin and smooth muscle actin, focal positivity for oestrogen receptor, individual positivity for Ki-67, and negativity for CD34 and S-100. The mass was removed laparoscopically, then placed in a specimen extraction bag and morcellated without spillage.

Figure 2  Retroperitoneal leiomyoma removed and morcellated by laparoscopic surgery.

Figure 3  The pedicle of the retroperitoneal leiomyoma was located 2 cm from the posterior peritoneum to the left of the rectum and was torsed two times.

OUTCOME AND FOLLOW-UP

The patient recovered well and was discharged on postoperative day 5. After 2 years of follow-up, no tumour recurrence was observed.

DISCUSSION

A literature review identified 14 cases[2,6-18] of RL torsion in the PubMed database from 1960 through 2023 (Table 1). The PubMed database was searched with the following search terms or keywords: “torsion AND (fibroid OR myoma OR leiomyoma) AND (English[Language]) AND (("1960"[Date-Publication]: "2023"[Date-Publication]))”, yielding 188 results. Among these, 175 studies were excluded: 40 were reviews or guidelines only; 18 were retrospective or prospective articles not related to RL torsion; 19 were case reports not related to torsion; 36 were case reports of uterine torsion; 22 were case reports of adnexal torsion; 37 were case reports of uterine myoma torsion; 1 was a case report of testis torsion; 1 was a case report of appendix torsion; and 1 was case report of primary omental torsion, leaving 13 publications for review[2,6,8-18]. One article was found through a search of the bibliographies of the other articles[7], for a total of 14 English reports of RL torsion found via the PubMed database.

Table 1 Comparison and review of reported cases of torsed retroperitoneal leiomyomas.

Ref.	Year	Age in years	Size in cm	Origin of torsed myoma	Preoperative diagnosis	Route of surgery for the leiomyoma
Walrond et al[2]	1973	59	20	Posterior wall of the antrum of the stomach	Undiagnosed	Laparotomy
Brieger et al[6]	1995	41	10	Greater omentum	Torsion of an ovarian cyst	Laparoscopy
Yeh et al[7]	1999	33	15	Broad ligament	Torsion of a pedunculated fibroid	Not specified
Tan et al[8]	2012	44	Not specified	Greater omentum	Acute appendicitis	Laparotomy
Park et al[9]	2013	45	7	Mesentery	Not specified	Laparoscopy
Narasimhulu et al[10]	2015	40	9.6	Anterior wall of the rectum	Parasitic fibroids with degeneration	Laparotomy
Hirayama et al[11]	2015	37	8.5	Greater omentum	Torsion of left ovarian tumour	Laparotomy
Cho et al[12]	2016	38	16	Greater omentum	Omental torsion	Laparotomy
Kaya et al[13]	2018	28	4.5	Round ligament	Undiagnosed	Laparoscopy
Bajis et al[14]	2018	47	25	Mesentery of the ileocaecal junction	Ovarian cyst torsion	Laparotomy converted from laparoscopy
Sofoudis et al[15]	2020	43	9	Intestinal tube	Not specified	Laparoscopy
Stebbings et al[16]	2021	39	10	Greater omentum	Appendicitis	Laparoscopy
Miles et al[17]	2021	48	19.3	Posterior wall of the antrum of the stomach	Myoma torsion	Laparoscopy
Lu et al[18]	2022	42	Not specified	Greater omentum	Not specified	Laparoscopy
Our patient	-	42	10	Broad ligament	Undiagnosed	Laparoscopy

The ages of the 15 patients, including ours, ranged from 33 years to 59 years, and the average age was 40.91 years. Eleven of the fifteen patients had a history of uterine leiomyoma surgery or were diagnosed intraoperatively with uterine leiomyomas.

The size of the fibroids was not recorded in 2 patients; the diameter of the fibroids of the other 13 patients was 4.5-25 cm, with a median of 10 cm and an average of 12.6 cm. The tumours mainly originated from the pelvic cavity, including the greater omentum in patients, the round ligament in 2 patients, the mesentery in 2 patients, the broad ligamentum in 1 patient, the anterior wall of the rectum in 1 patient, the intestinal tube in 1 patient, the bladder peritoneum in 1 patient and the posterior peritoneum in 1 patient. Only one tumour originated from the antrum of the upper abdomen.

Seven of the fifteen patients also presented with uterine leiomyomas that were identified intraoperatively, and three did not have complications. Complication information for the other 5 patients was not provided.

Six patients had a previous history of uterine fibroid surgery, including abdominal myomectomy in two patients, laparoscopic hysterectomy in one patient and laparoscopic myomectomy in three patients, while six patients had no surgical history. For all patients who underwent laparoscopic surgery, a morcellator was used. The surgical history of 3 patients was not indicated.

The aetiology of RL is unclear, but it mainly occurs in female patients, especially in perimenopausal or postmenopausal patients, and more than 40% of female patients with RL also have previous or concurrent uterine leiomyoma[1,19].

Subserous leiomyoma detachment and implantation may be a characteristic of RL. When the pedicle is narrower than the tumour diameter, a pedicled subserous fibroid may occasionally detach from the uterus and derive its blood supply from the adhesive tissue[20]. In another 2 patients with RL torsion[6,11], no uterine leiomyoma was found via preoperative ultrasound or intraoperative operation, but a subserous leiomyoma had been previously detected on ultrasound. It was speculated that the subserous fibroid had exfoliated from the uterus and reimplanted as an RL. A small area on the serosa was found intraoperatively in 1 patient and was presumed to be where the leiomyoma was once attached[6].

The seeding hypothesis is also considered an important pathogeny of the RL. Parasitic fibroids are thought to account for a large proportion of RLs. It is believed that parasitic leiomyomas can develop after surgery on uterine fibroids by seeding residual tissue fragments in the abdominal cavity[6,16,21-25]. The duration of steroid exposure after surgery might be a risk factor for the development of parasitic myomas[26]. Among the 15 patients with RL torsion, 6 had a previous history of leiomyoma surgery, including laparoscopic hysterectomy for 1 patient, laparoscopic myomectomy for 3 patients, and abdominal myomectomy for 2 patients. Three, two, three and six parasitic leiomyomas were detected intraoperatively in the 4 patients among these with a history of morcellation[8,10,15,18], while only one fibroid was found in the 2 patients with a history of abdominal myomectomy[9,12]. A greater number of parasitic leiomyomas were detected intraoperatively in patients with a history of morcellation, suggesting that laparoscopic morcellation may be more likely to lead to the development of parasitic leiomyomas. The use of a containment bag for decreasing the burden of tissue dissemination may mitigate the risk of tissue spread during morcellation[26]. Therefore, in patients with abdominal or pelvic pain, if there is a history of uterine fibroid surgery, especially hysterectomy or myomectomy with morcellation, torsion of parasitic myomas should be considered.

It is assumed that Caesarean section can also lead to the seeding of leiomyoma cells[16]. When Caesarean section is performed, uterine leiomyomas may be breached and seeded during the opening and closure of the uterine cavity. Among the 15 patients with RL torsion, 3 had undergone neither previous laparoscopic morcellation nor abdominal myomectomy but did have a history of Caesarean section[14,16]. The patient described by Stebbings et al[16], who had three elective Caesarean section deliveries but no other surgical history, was confirmed to have RL torsion complicated with uterine leiomyomas.

However, the seed and soil hypothesis cannot explain all of the cases. In the case reported by Bajis et al[14], the uterus was confirmed to be normal intraoperatively, which indicated that the torsed myoma may not have been a parasitic tumour. Our patient, whose case was confirmed to have RL torsion complicated by uterine leiomyomas intraoperatively, had no other uterine surgery history but underwent a Caesarean section 17 years prior to identification of the torsion. However, given the long time between the Caesarean section and the RL torsion, there may be other causes for the development of the RL. These findings suggest that these RLs may be primary RLs.

Most RLs are positive for oestrogen receptor or progesterone receptor and have pathological and histological characteristics similar to those of uterine leiomyomas[1,19], which suggests that these two types of leiomyomas may have the same aetiological basis. Stutterecker et al[27] speculated that the origins of RL may be embryonal remnants (e.g., the tubes of Müller and Wolff) or local vessel musculature. Pathologic and immunohistochemical findings of most RLs are similar to those of uterine fibroids but still cannot explain the origins of nonpelvic RLs, receptor-negative RLs, or RLs in males[1,19]. The pathogenesis of RL may involve multiple mechanisms and be related to multiple factors.

Given the rarity of RLs, RL torsion is exceptionally rare. Leiomyoma torsion, a known cause of acute abdominal pain, occasionally occurs in pedicled subserous uterine fibroids. The incidence of leiomyoma torsion has been reported to be less than 0.25% in patients who undergo surgical treatment for subserous uterine leiomyomas[28]. Factors associated with leiomyoma torsion include the presence of a pedicle, a larger size and weight, the size of the vascular pedicles of the leiomyoma, and pregnancy[3,28]. Like uterine leiomyoma torsion, a larger size and pediculation are associated with RL torsion. The 15 torsed RLs were all pedicled. Except for 2 patients whose tumour size was unknown, all the tumours were no less than 4.5 cm in size, and 6 of them were no less than 10 cm in size.

The most prominent clinical symptom of RL torsion was abdominal pain, which was present in all 15 patients. Once RL torsion occurs, in addition to the similar symptoms of uterine leiomyoma torsion, such as abdominal pain, nausea, and fatigue[9,12,16,17,28], different symptoms may also occur depending on the site of the lesion. Sofoudis et al[15] reported on a 43-year-old woman with intestinal parasitic myoma torsion who presented with diffuse abdominal pain, gastrointestinal disturbance and constipation.

As in cases of appendicular torsion and uterine fibroid torsion, in cases of RL torsion, the most common clinical signs are tender masses in the pelvis and abdominal cavity, followed by peritoneal irritation, distress and fever.

Although RLs do not seem to have any specific imaging features, imaging examinations, including ultrasound, computed tomography (CT) and MRI, are valuable for the preoperative diagnosis of RL torsion. These methods can aid in detecting pelvic or abdominal boundary masses and also help to explore the relationship between the masses and the uterus[3,7,29,30].

The possible imaging features of RLs include a well-circumscribed mass separate from the uterus and adnexa, no enhancement, a torsed pedicle, and ascites. Torsed RLs are often separate from both the uterus and adnexa. However, when the RL is adjacent to or even adhered to the uterus, as with the RLs observed in our study and in three other studies[7,16,17], it is more likely to be misdiagnosed as a uterine fibroid.

Torsed tissues, such as the adnexa, may not demonstrate any enhancement compared to normal tissues on CT and MRI[3], and the torsed RL demonstrated the same characteristics[10,11]. On ultrasound, the spectral Doppler flow within the vascular pedicle and the mass itself is sometimes absent[3].

A torsed pedicle can yield a more confident diagnosis of torsion. The “whirlpool sign” and “swirl sign”, indicating the appearance of vascular pedicular torsion, can be demonstrated on cross-sectional images[3,17]. When omental torsion occurs, a whirling pattern of fatty streaks within the omentum, which is considered a relatively characteristic feature of omental torsion, can be observed on coronal views[12].

Ascites is another sign of RL torsion[7]. Among the 15 patients identified here and in the review, effusion was found in our study and 5 others[7,8,12,14,16]. Ascites may first be caused by obstruction of the venous return; then, gangrene, inflammation and even bleeding can occur in torsed RLs[3-5], as can exudation of the surrounding tissues.

Notably, when the mass is outside or high within the pelvis, transvaginal ultrasonography may not visualize the area well[7], and transabdominal ultrasonography or CT or MRI scans are necessary. This was demonstrated in the case reported by Park et al[9], in which transvaginal ultrasonography was the only imaging examination performed before surgery, revealing that the torsed mass was in the right paracolic gutter and was not detected preoperatively.

Due to the lack of specific clinical and imaging features, it is difficult to make a preoperative diagnosis of leiomyoma torsion[3,28]. Moreover, the rarity and uncertain location of the RL increase the difficulty of preoperatively diagnosing RL torsion. However, imaging techniques are important and useful for diagnosis, not only because they can help to define the location and nature of the mass but also because they can be used to exclude other intraperitoneal lesions[4].

The main treatment for RL torsion is surgery, most commonly involving myomectomy. If the torsion is not relieved in time, it may be followed by gangrene, peritonitis, haemoperitoneum, or even shock[2-5]. Therefore, the possibility of RL torsion should be considered in patients with pelvic masses associated with acute abdominal pain and other related symptoms. In addition, if the diagnosis is unclear, surgical exploration should be considered to confirm the diagnosis in a timely manner to reduce the risk of other complications. Laparoscopic exploration may be a good option for making a clear diagnosis and excision.

CONCLUSION

Overall, the findings of this case suggest that when a patient presents with a pelvic mass complicated with acute abdomen, even if the mass is far from the uterus and accessory organs, the possibility of torsion should still be considered. Laparoscopic exploration may be a good option for making a clear diagnosis and excision.

ACKNOWLEDGEMENTS

The authors would like to thank Dr. Chen Hao for his contribution to the pathological examination.