Abstract
Case 1 ; An 85-year-old man was admitted to our hospital with severe abdominal pain. A computed tomography (CT) showed multiple concentric ring sign at the left lower quadrant of the abdomen, and we diagnosed it as colonic intussusception. An emergent operation was performed. A tumor derived from the transverse colon invaginated into the sigmoid colon. Immunohistological examination revealed undifferentiated carcinoma of the colon.
Case 2 ; An 82-year-old man was referred to our hospital due to melena, and was diagnosed as intussusception. The elective surgery was done and revealed that the tumor derived from the sigmoid colon invaginated into the sigmoid colon antegradely with a triple wall. The resected specimen showed undifferentiated carcinoma of the sigmoid colon.
Colonic intussusception due to undifferentiated carcinoma is extremely rare, and so far three cases have been collected. All the cases were aged-male older than 70 years. The leading tumors were located in the sigmoid or transverse colon and appeared as a large elevated tumor more than 4.5 cm in diameter. We did not find any radiological findings specific for the intussusception due to undifferentiated adenocarcinoma. More cases are needed to explore its clinical and pathologic features.
