Teaching Case

16-year-old male with a 1-month history of intermittent lower abdominal pain. Laboratory parameters were unremarkable.

A 16-year-old male was admitted to the hospital with clinically suspected acute appendicitis. He had a 2 weeks history of abdominal pain in the mid lower abdomen and the right lower quadrant. He reported a similar episode of pain 2 weeks earlier. Physical examination revealed tenderness of the mid lower abdomen. Laboratory parameters were within the normal range. The patient underwent a sonographic examination and an abdominal helical CT scan. In addition, a pertechnetate radionuclide study was performed.

Meckel’s diverticulum (MD) is the most common congenital abnormality of the small intestine, occurring in approximately 2% of the population. Complications become clinically apparent in up to 20%, of which the most common are intestinal obstruction, diverticulitis, and bleeding. Although MD and its complications can be demonstrated by different imaging methods, diagnosis may be difficult (1). Most important imaging methods are: small-bowel follow-through or enteroclysis; radionuclide studies; angiography; CT; sonography. Barium studies can demonstrate MD as a single diverticulum arising from the distal ileum. It may also present as a polypoid filling defect in cases of inverted diverticula (2). Such an inverted diverticulum may become the lead point for an intussusception. Overlap of intestinal loops or an obstructed diverticular neck due to inflammation may prevent successful diagnosis. Radionuclide scans can identify ectopic gastric mucosa (99mTc-pertechnetate) or the site of gastrointestinal bleeding (99mTc-labeled RBCs) (1). A negative test doesn’t exclude a MD because only 20% of cases contain ectopic gastric mucosa. Angiographic diagnosis is based on visualisation of an anomalous artery (persistent vitellointestinal artery), a dense capillary network in the diverticulum, or extravasation of contrast material in actively bleeding patients (3). CT and Sonography are usually unable to distinguish between a diverticulum and intestinal loops. In cases of complications, a tubular structure adjacent to a bowel loop and possibly with peridiverticular inflammation may be demonstrable (1,4). A “target sign” is indicative of intussusception. In this patient both ultrasonography and CT showed a tubular structure adjacent to small-bowel loops and a small abscess formation.