A case of retrograde intussusception due to transverse colon cancer detected by abdominal ultrasonography

A 78-year-old female patient presented to our hospital with abdominal pain and melena. Abdominal ultrasonography detected a multiple concentric ring sign and retrograde invagination mass near the hepatic flexure. Colonoscopy revealed a 40-mm diameter type 1 tumor in the transverse colon near the splenic flexure, and the biopsy specimen demonstrated a well-differentiated adenocarcinoma. Retrograde intussusception due to transverse colon cancer was diagnosed, and laparoscopic transverse colon resection with lymph node dissection was performed. The resected specimen revealed a 48×40mm diameter type 1 tumor in the transverse colon and was diagnosed as pT2N0M0 pStage I. Contrast-enhanced computed tomography was unavailable, but real-time assessment of the invaginated mass and bowel blood flow was possible by abdominal ultrasonography, which was useful in determining the diagnosis and treatment strategy.