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Answer: Inverted Meckel Diverticulum
Helical computed tomography of the abdomen and pelvis after contrast shows the “target”-shaped area within 1 of the small-bowel loops, consistent with ileoileal intussusception (Figure 1). The patient underwent resection of the mass with an 8-cm margin from each side. The small bowel was then reconnected with a primary anastomosis. The patient was discharged home on postoperative day 4.
Helical computed tomographic scan after oral contrast shows the characteristic “target”-shaped lesion within 1 of the distal small-bowel loops, indicating an ileoileal intussusception.
Pathologic examination of the specimen confirmed the diagnosis of inverted Meckel diverticulum with heterotopic pancreatic tissue and acute ischemic enteritis with serositis. Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract, occurring in 2% to 3% of the population1and often asymptomatic. Clinical symptoms arise from complications, which occur in 4.2% to 6.4% of those harboring the diverticulum.2,3The lifetime risk of complications is likely independent of age, although they are more common in men than women.4
Intestinal obstruction is the most common complication in adults with Meckel diverticula.5This may be caused by intussusception, volvulus, luminal obstruction from an inverted diverticulum, diverticulitis or a foreign body inside the diverticulum, inclusion of a diverticulum into a hernia, or neoplastic obstruction.
Heterotopic pancreatic tissue is found in 5% to 16% of resected Meckel diverticula.6,7The heterotopic pancreatic tissue may be located in the distal tip of the diverticulum and serve as a lead point for intussusception.
Only a few cases of inverted Meckel diverticulum have been reported.6,8Clinically, these patients present with bleeding, melena, and acute abdominal pain. Our case is unique because the patient presented with chronic diarrhea and intermittent abdominal pain.
Although a preoperative diagnosis of intussuscepted Meckel diverticulum has traditionally been based on an enteric contrast study or ultrasonography, computed tomography has been shown to be equally accurate if not more so.9A classic feature of this ileoileal intussusception is the target lesion, which helped the diagnosis in this case.
Correspondence:David Jacobsen, MD, Department of Surgery, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115.
Accepted for Publication:May 25, 2005.
Image of the Month—Diagnosis. Arch Surg. 2006;141(2):215–216. doi:10.1001/archsurg.141.2.216
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