Intended for healthcare professionals

Endgames Case Review

An uncommon right iliac fossa mass in an older woman

BMJ 2017; 358 doi: (Published 27 July 2017) Cite this as: BMJ 2017;358:j3279
  1. Thomas H Newman, CT1,
  2. Eline A Caine, CT1,
  3. Kathryn Lynes, surgical ST7,
  4. Joseph Sebastian, colorectal surgeon
  1. Queen Elizabeth the Queen Mother Hospital, East Kent Hospitals University NHS Foundation Trust, Margate, UK
  2. Correspondence to Thomas Newman thnewman{at}

A 74 year old woman was referred to the general surgery clinic after she found a lump in her lower abdomen, which she had noticed 4-5 weeks previously. She also reported a feeling of not completely emptying her bowels, and reduced frequency of bowel opening. She had noticed no blood or mucus in the toilet bowl, and had not had abdominal pain, lower urinary tract symptoms, or vaginal discharge. She had lost two stone (12.7 kg) in weight over a few months, but she attributed this to a recent diagnosis of diabetes mellitus. Her surgical history was a total abdominal hysterectomy and bilateral salpingo-oophorectomy in 1996 for menorrhagia. On examination, she had a large non-tender soft swelling in the right iliac fossa but no evidence of inguinal, femoral, or pfannenstiel incisional hernia. Blood tests were unremarkable, and a colonoscopy identified only mild diverticular disease. A computed tomography (CT) scan of her abdomen and pelvis was taken (fig 1).

Fig 1
Fig 1

Sagittal slice of a computed tomogram of the abdomen with intravenous and oral contrast


  • 1. What is the differential diagnosis?

  • 2. How is this diagnosis defined by the anatomy of the abdominal wall?

  • 3. What are the treatment options?


1. What is the diagnosis and what are the differential diagnoses?

Short answer

This is a Spigelian hernia. The differential diagnoses include alternative abdominal wall hernias (eg, incisional, paraumbilical) and soft tissue lesions (eg, lipoma, abdominal wall tumour). Spigelian hernias commonly present without a mass.


Spigelian hernias are rare, accounting for about 1% of abdominal wall hernias.1 They generally present in one of three ways: with pain, a lump, or a small bowel obstruction. One large case series identified that 42.8% of their patients presented with chronic pain, 28.5% with obstruction, 17.9% had a lump, and 10.7% were incidental findings.2

As the hernial sac generally lies within an interparietal plane (below the external oblique aponeurosis), there is commonly no obvious mass.3

In cases of abdominal pain, the differential diagnosis might include appendicitis, acute diverticulitis, and spontaneous haematoma of the rectus sheath. Abdominal pain, especially in the right iliac fossa, can present a difficult diagnostic scenario, therefore ultrasound or CT scanning might be needed to make a diagnosis. There are documented cases which have been found on diagnostic laparoscopy in presumed appendicitis.4

When presenting as a mass or swelling, differentials include an alternative abdominal wall hernia (eg, incisional, paraumbilical), soft tissue lesions (eg, lipoma, abdominal wall tumour), and intra-abdominal masses (eg, malignancy). If there is any uncertainty, then further imaging with ultrasound or CT scan should be considered. An ultrasound is often a better initial investigation if there is clinical suspicion of an abdominal wall hernia,5 especially in a young patient where a high dose of radiation should be avoided if possible.

Spigelian hernias typically have a small neck, increasingly the risk of strangulation and potentially small bowel obstruction.6

2. How is this diagnosis defined by the anatomy of the abdominal wall?

Short answer

A Spigelian hernia is the protrusion of an abdominal viscus, peritoneum, or preperitoneal fat through a defect in the Spigelian aponeurosis, located between the rectus abdominis medially and the semilunar line laterally (fig 2, fig 3).

Fig 2
Fig 2

Sagittal slice of a computed tomogram of the abdomen with intravenous and oral contrast showing a right sided Spigelian hernia. 1. Hernial sac containing bowel. 2. Right rectus abdominis. Dotted line: neck of hernia

Fig 3
Fig 3

Axial slice of a computed tomogram of the abdomen with intravenous and oral contrast


The Spigelian aponeurosis is widest and most susceptible to herniation in the area between the interspinous plane and a parallel plane 6 cm cranially to this, which is called the “Spigelian hernia belt.”7 Below the arcuate line, the abdominal wall lacks a posterior sheath and is therefore more prone to herniation.

Spigelian hernias often lie interparietally and specifically between the internal and external oblique aponeuroses. It is important to be aware of the anatomy of the abdominal wall during laparoscopic port and abdominal drain siting, as avoiding the Spigelian aponeurosis can reduce future risk of Spigelian hernia formation.8

3. What are the treatment options?

Short answer

Management is either conservative or surgical, with both open and laparoscopic techniques being well established.


Traditionally, an open approach was taken to repair Spigelian hernias, but over the past 20 years several laparoscopic techniques have been used effectively.46 Open repair of a Spigelian hernia is similar to other abdominal wall hernia repairs, whereby sutures with or without a mesh are used to close the defect. Laparoscopic methods documented include intraperitoneal onlay mesh repair, transabdominal preperitoneal repair, and total extraperitoneal repair.1

The choice between the techniques is dependent on surgical preference and patient co-morbidities. In the only randomised controlled trial of Spigelian hernia repair, a laparoscopic approach was shown to statistically significantly reduce hospital stay and morbidity compared with an open approach.9

Patient outcome

The patient experienced no peri-operative or postoperative complications, and one month on from her operation the mass is no longer present and she is pain-free.


  • We have read and understood BMJ policy on declaration of interests and declare no competing interests.

  • Patient consent obtained.

  • Provenance and peer review: not commissioned; externally peer reviewed.


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