Type 4 appendiceal diverticulum within a de Garengeot hernia

A de Garengeot hernia is defined as an incarcerated femoral hernia containing the vermiform appendix. We describe the case of a patient with a type 4 appendiceal diverticulum within a de Garengeot hernia and delineate valuable learning points. A 76-year-old woman presented with a 2-week history of a non-reducible painless femoral mass. Outpatient ultrasonography demonstrated a 36mm × 20mm smooth walled, multiloculated, partially cystic lesion anterior to the right inguinal ligament in keeping with an incarcerated femoral hernia. Intraoperatively, the appendix was found to be incarcerated in the sac of the femoral hernia and appendicectomy was performed. Histopathology demonstrated no evidence of inflammation in the appendix. However, an incidental appendiceal diverticulum was identified. It is widely recognised that a de Garengeot hernia may present with concomitant appendicitis, secondary to raised intraluminal pressure in the incarcerated appendix. Appendiceal diverticulosis is also believed to develop in response to raised pressure in the appendix and may therefore develop secondary to incarceration in a de Garengeot hernia. To our knowledge, only one such case has been described in the literature. A de Garengeot hernia is a rare entity, which poses significant diagnostic challenges. A high index of clinical suspicion is necessary as these hernias are at particularly high risk of perforation and so prompt surgical management is paramount.