An 8-year-old boy presented with right iliac fossa pain and vomiting for 1 day. He had classical signs of peritoneal irritation in the right iliac fossa, was afebrile, and his white cell count was upper normal. He was diagnosed with acute appendicitis and an open appendectomy was undertaken. At laparotomy, a copious amount of serous discharge was noted and the omentum was shifted towards right iliac fossa. The appendectomy was done and unfortunately–although the appendix was only hyperaemic–no further exploration was attempted.

Early postoperatively, the patient developed a clinical picture of small bowel obstruction and was, therefore, re-explored through the same incision. At the second operation, a loop of terminal ileum was found to be incarcerated by a mesodiverticular band (figs 1 and 2). Resection of the pathologic bowel loop together with the band was done. The postoperative course was unremarkable.

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Figure 1 Internal herniation of a loop of small bowel underneath a fibrous band.

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Figure 2 The mesodiverticular band extends between the tip of Meckel’s diverticulum and the mesentery of the ileum.

Note the vascularity of the band manifested by bleeding.

Mesodiverticular bands are fibrovascular bands that extend between the tip of Meckel’s diverticulum and the small bowel mesentery.1 Internal herniation of a loop of small bowel underneath the band may result in small bowel obstruction.2

In our case, the intraoperative diagnosis of acute appendicitis was incorrect, as the appendix was hyperaemic–probably secondary to the nearby inflammatory process–but not overtly inflamed. Based on this misdiagnosis, the terminal ileum was not explored and the actual pathology was missed.

From this case it can be suggested that internal herniation of the terminal ileum secondary to a mesodiverticular band can mimic acute appendicitis, especially in the early stage before intestinal obstruction is clinically apparent.