Spigelian hernias are a rare type of hernia through the Spigelian aponeurosis, whose contents commonly include omentum or small bowel. In the absence of incarceration or strangulation, they can be difficult to diagnose clinically. In the emergency setting, they can present rarely as a painful abdominal mass and computed tomography provides a reliable diagnostic imaging modality. We report an emergency presentation of a Spigelian hernia containing the appendix. KeywORdsSpigelian hernia -Appendix -Computed tomography -Sonography -Appendicectomy Case historyA 74-year-old man presented acutely to the accident and emergency department of a district general hospital with a 5-day history of absolute constipation. This was associated with a large, painful swelling in the right lower quadrant of the abdomen. He had complained of a much smaller 'lump' in this area 'on and off' for several months prior to his acute admission. He was nauseous but with no vomiting. Systemic enquiry revealed only some hesitancy on urination, which had been present for several months. Past medical history included a previous duodenal ulcer, Parkinson's disease and previous pulmonary embolisms following orthopaedic injuries, for which he was taking long-term warfarin. His only other regular medications were simvastatin and ropinirole.On physical examination, the patient was apyrexial, with a firm, tender mass in the right iliac fossa. Digital rectal examination found a smoothly enlarged prostate but no other abnormality. Routine blood tests including haemoglobin, white cell count, C-reactive protein, liver function tests, and urea and electrolytes were all normal, as was dipstick urinalysis. His international normalised ratio was 2.9.Given the history of absolute constipation in association with a right iliac fossa mass, computed tomography (CT) of the thorax, abdomen and pelvis was performed as the first radiological investigation. This showed a hernia at the inferolateral aspect of the right rectus abdominis muscle containing the appendix from its caecal root (Figs 1-4). Minimal inflammation of the caecal pole was seen, along with free fluid and inflammation in the surrounding herniated fat, suggesting a degree of vascular compromise although the appendix itself did not appear significantly thickened. The hernial defect measured 21mm in diameter. There was a trace of free fluid in the pelvis but no suggestion of a tumour.The patient was listed for an emergency repair and appendicectomy. At operation, an oblique incision was made in the right iliac fossa and the external oblique aponeurosis was opened to reveal the hernial sac. The neck of the sac was exposed and the hernial defect at the edge of the right rectus abdominis muscle identified. The sac was opened to enter the peritoneal cavity. The sac contained a small amount of fluid and a macroscopically normal appearing appendix. A standard open appendicectomy was performed before closing the peritoneum. The hernial defect was closed with 2/0 Vicryl ® (Ethicon, Somerville, NJ, US) by...