A 79-year-old man presented with sudden onset of lower abdominal pain and rectal bleeding. He had a known lung cancer treated with chemotherapy for 2 years and recent admission for acute cholecystitis complicated by pneumonia and pleural effusion. A sigmoid colon cancer involving almost half of the bowel circumference was also diagnosed on that previous admission but not treated due to his comorbidities at the time. On examination his abdomen was soft with focal tenderness in the lower abdomen. His laboratory tests showed a mild leukocytosis (10,100 /mm3), an elevated C-reactive protein (37.7 mg/L), a low albumin (18 g/L), and moderate liver dysfunction (AST 134 U/L and ALT 149 U/L). These results were not much different from his previous admissions. His creatine kinase level was normal.
The patient underwent colonoscopy the day following hospitalization and a large, dome-like, white, translucent edematous colonic mucosa was seen that almost occluded the rectum (Figure 1). At the edge of the dome, a tumor was also observed, which suggested colonic intussusception to the rectum with a sigmoid colon cancer as a lead point. Abdominal computed tomography (CT) demonstrated a sausage-like intussusceptum with a high CT attenuation core (mesenteric vessels) surrounded by tissue of low CT attenuation (mesenteric fat; Figure 2 white arrow). This appeared within the rectum (the intussuscipien), which was edematous and had an intermediate CT attenuation (Figure 2 black arrow).
In contrast to children, adult intussusception is a rare disorder and is usually not idiopathic. Approximately half of all intussusceptum lead points are malignancies. The most frequent type of intussusception is entero-enteric, and the colo-colonic type, as in the present case, only accounts for 6%. Colonic intusscusception, however, is more commonly associated with malignancies than enteric intussusception (63 vs. 20%). Due to a high rate of tumors or malignancies, adult intusscusception should be treated by surgery. The present case was not managed surgically because of the patient's poor functional status. As there was no ischemic color change of the colonic mucosa to suggest ischemia or infarction on colonoscopy, reduction was attempted using water-soluble contrast medium enema. This successfully reduced the intussusception and thereafter the abdominal pain and rectal bleeding resolved. Unfortunately the patient's respiratory status worsened due to a pneumonia and he died 4 days later.