Background: Although colonoscopy is widely used and considered safe procedure for diagnosing and treating
gastrointestinal tract diseases, life-threatening complications, including perforation and bleeding,
may occur.
Case Report: A 56-year-old woman underwent colonoscopy to investigate anemia. After colonoscopy, abdominal distension, pain, mild swelling in her neck and face. She developed some difficulty breathing
that was not severe enough to reduce oxygen saturation. Upright chest radiograph and thoracalabdominal computed tomography demonstrated pneumopericardium, pneumomediastinum, subcutaneous emphysema, and pneumoretroperitoneum. Exploratory laparotomy was performed owing to the increase in the subcutaneous emphysema and abdominal pain. At laparotomy, perforation at the splenic flexure of the colon at the retroperitoneal region was detected. The
defect was repaired with primary closure.
Conclusions: Perforation during diagnostic colonoscopy may be caused by mechanical, pneumatic pressure and transmural electrocautery injuries. Intraabdominal air may be absent in retroperitoneal colonic perforation. Physicians should be aware of different presentation patterns of retroperitoneal
colonic perforation due to colonoscopy.

Keywords: Colonoscopy, perforation, retroperitonium, Diagnosis, management