Torsion of a parasitic leiomyoma: a rare but important differential in women presenting with lower abdominal pain

Abstract

A 39-year-old multiparous Afro-Caribbean woman attended the emergency department with sudden-onset severe right iliac fossa pain. Her inflammatory markers were mildly elevated. Computerised tomography of the abdomen demonstrated features of fat stranding in the right iliac fossa suspicious of acute appendicitis. The scan also noted uterine leiomyomas. The patient was taken to theatre for an emergency diagnostic laparoscopy where her appendix was found to be macroscopically normal. A necrotic heavily calcified parasitic leiomyoma was seen in the right adnexa, free of the uterus and adherent to the greater omentum on a long torted pedicle. The parasitic leiomyoma was successfully removed piecemeal laparoscopically. Complications of leiomyomas, namely, torsion and necrosis, are important differentials in women presenting with sudden-onset lower abdominal pain. A history of sudden-onset severe lower abdominal pain with a background of known leiomyoma should prompt the clerking surgeon to consider a complication of leiomyoma as part of the differential diagnoses.

Background

Over half of the annual 600 000 emergency admissions in England under the care of general surgeons present with abdominal pain.¹ Appendicitis is a key differential in the acute abdomen, with 50 000 emergency appendicectomies being performed annually.² Nevertheless, uterine leiomyoma (UL) and their complications remain an important differential too.³ ULs occur in 20%–50% of women over the age of 30, making them the most common tumour of the female reproductive system and the leading reason for hysterectomy.^{4 5} The incidence of UL has been found to be three times more common in women of black ethnicity compared with white ethnicity.⁶ The International Federation of Gynaecology and Obstetrics categorises UL into four main subtypes, namely, submucosal, intramural, transmural and subserosal.⁷ Parasitic leiomyoma (PL) is considered a subtype of UL and is extremely rare.⁸

Case presentation

A 39-year-old woman of Afro-Caribbean descent attended the emergency department complaining of sudden-onset lower abdominal pain that woke her from sleep. She characterised the pain as labour-type pain and described its severity as 8/10 localised to the right iliac fossa. The pain was worse on movement and coughing and was associated with a loss of appetite. There were no associated lower urinary tract symptoms. The patient did not report any nausea, vomiting or a change in bowel habit. Her last menstrual period was 10 days prior to presentation. The patient had three elective caesarean section deliveries but nil other surgical history. The patient was not taking any regular medications and had no known drug allergies. She was a lifelong non-smoker and did not drink any alcohol. There was no relevant family history of note.

On admission, her pulse was 88 beats per minute, her blood pressure was 168/99 mm Hg and she was afebrile. She had a respiratory rate of 15 per minute and saturating at 97% on room air. On examination she was tender in the right iliac fossa with localised peritonism. She had no organomegaly, palpable masses or hernias.

Investigations

The patient’s blood tests showed marginally raised inflammatory markers on admission with a white blood cell count of 9.3×10⁹/L (4.0–11.0) and a C reactive protein of 44 mg/L (0.0–5.0). Her urine dipstick bedside test and urine beta human chorionic gonadotropin (beta-hCG) pregnancy test were both negative. Due to the sudden nature of the patient’s symptoms and localised peritonism, an emergency out-of-hours CT scan of the abdomen and pelvis with intravenous contrast (omnipaque) was performed. This demonstrated a contrast-enhanced appendix up to 9 mm with surrounding fat stranding and minimal free fluid, suggestive of acute appendicitis. There was no evidence of perforation. Significantly calcified ULs measuring 9.0 cm×5.5 cm and 4.4 cm×5.0 cm were noted (figures 1–3). Her ovaries were reported as normal.

Figure 1.

Computerised tomography (portal venous phase) in coronal plane showing a calcified parasitic leiomyoma with two intrauterine calcified leiomyomas (blue arrows).

Figure 2.

Computerised tomography (portal venous phase) in sagittal plane showing a calcified parasitic leiomyoma with two intrauterine calcified leiomyomas (blue arrows).

Figure 3.

Computerised tomography (portal venous phase) in axial plane showing a calcified parasitic leiomyoma with two intrauterine calcified leiomyomas (blue arrows).

Based on the above findings, the patient was consented for a diagnostic laparoscopy and appendicectomy.

Differential diagnosis

As the patient presented with right iliac fossa pain, raised inflammatory markers and CT scan findings suggestive of acute appendicitis, appendicitis was considered the most likely diagnosis. As her abdominal pain was sudden in onset, severe and unilateral, ovarian torsion was also considered as a differential diagnosis.

Treatment

The patient was admitted under the general surgeons and managed with intravenous Hartmann’s solution and analgesia (intravenous paracetamol and morphine). After the CT scan, she was started on intravenous amoxicillin, metronidazole and gentamicin as per the local guidelines for intra-abdominal infection. She was kept nil by mouth and commenced on venous thromboembolism prophylaxis.

The patient was taken to theatre for emergency diagnostic laparoscopy. Intraoperatively, her appendix was found to be macroscopically normal (figure 4). Suprapubic omental adhesions were divided, revealing a 10 cm necrotic, torted lesion on a long pedicle. This was free of the uterus and adherent to the greater omentum on a long torted pedicle (figure 5). Note was also made of a multifibroid uterus and a subserosal fundal leiomyoma adherent to the abdominal wall. Input from the gynaecology team was sought only intraoperatively as there was no suspicion of a gynaecological pathology preoperatively. The ovaries and uterus were examined by the gynaecology team to confirm the diagnosis and rule out any other occult pathology. The torted PL was divided from its pedicle using a laparoscopic ultrasonic scalpel (figure 6) and extracted piecemeal using a bone nibbler due to its highly calcified nature (figure 7).

Figure 4.

Intraoperative photograph showing necrotic fibroid situated in the right side of the pelvis with overlying macroscopic normal-looking appendix (blue arrow).

Figure 5.

Intraoperative photograph showing necrotic fibroid with long torted omental pedicle (blue arrow).

Figure 6.

Intraoperative photograph of mobile necrotic fibroid mobilised to the right upper quadrant inferior to the liver.

Figure 7.

Intraoperative photograph showing removed fibroid piecemeal.

The patient received three further doses of intravenous antibiotics postoperatively as per local guidelines.

Outcome and follow-up

There were no postoperative complications, and the patient was discharged the day after her operation on thromboprophylaxis. She was seen in gynaecology outpatient clinic ten days later. Histology reported features in keeping with smooth muscle neoplasm with infarction/marked hyaline degeneration and dystrophic calcification. Haemorrhage and acute inflammation were noted. No frank pleomorphism was seen, and mitoses were difficult to find. The changes were presumed to represent infarcted leiomyoma with degenerative changes due to loss of blood supply. The patient was noted to be recovering well, and routine clinic follow-up was arranged for 3 months time.

Discussion

The aetiology of PL is unclear. First described in 1909, PLs were previously thought to be a progression of pedunculated subserosal UL, which eventually detach from the uterus and leach onto organs in close proximity and develop neovascularisation from these organs, commonly the omentum and mesenteric vessels.^{9 10} New research however suggests a different hypothesis. With the advent of laparoscopic morcellation, it is hypothesised that accidental seeding of tissue left behind during the morcellation process can lead to the formation of PL.¹¹ Interestingly, although our patient did not undergo previous laparoscopic morcellation, she did have three prior caesarean sections, raising the possibility of breach of UL and seeding during opening and closure of the uterine cavity.

PL and their complications are extremely rare and are often diagnosed incidentally following vague abdominal symptoms.^{12 13} Case series of PL within the literature have demonstrated a trend towards incidence within women previously undergoing laparoscopic morcellation.¹⁴ Having said that, incidental findings of PL within women not having undergone previous abdominal surgery have also been reported in a handful of cases. Salih et al reported a case of a woman presenting with upper abdominal fullness and vague symptoms of nausea, shortness of breath and palpitations. She was found to have a PL within the epigastrium attached to the greater omentum.¹⁵ Khan et al reported a case of PL attached to the greater omentum presenting with high-grade small bowel obstruction.¹⁶ Bhargava et al reported a case of postmenopausal woman with PL presenting as an inguinal hernia.¹⁷

The treatment of PL regardless of location is by ligation of the vascular pedicle and extraction of the PL, either laparoscopically or open.¹⁵

Though very rare, surgeons should be aware of PL and their complications, especially due to the vagueness of their symptomatology. Complications of PL should be considered in all female patients with known UL and particularly those having undergone prior uterine surgery.

In this case, there was no acute appendicitis identified. The authors suspect that the inflammation around the appendix identified on CT was in fact reactive and secondary to its close proximity to the necrotising PL. Preoperative gynaecological examination, including transvaginal ultrasound scan, may have improved diagnostics for this patient.

Learning points.

• Uterine leiomyomas (ULs) occur in 20%–50% of women over the age of 30 and are three times more common in women of black ethnicity compared with white ethnicity.⁴

• Complications of ULs are an important differential in the acute abdomen. Effective teamwork and communication between general surgery and gynaecology are required to direct and achieve appropriate management in these cases.

• Parasitic leiomyomas (PLs) are extremely rare, but their incidence is reported to be increasing as result of modern surgical techniques.

• A torted PL can present with sudden-onset severe abdominal pain mimicking acute appendicitis.