Colonic intussusception: clinical and radiographic features.

OBJECTIVE: The purpose of this article is to comprehensively survey all CT-detected ileocolic and colocolic intussusceptions at a cancer institute.

MATERIALS AND METHODS: Using the free-text string "intus," the radiology information database of Memorial Sloan-Kettering Cancer Center was searched over a 13.5-year period for abdominopelvic CT scan reports. Images were rereviewed by an attending radiologist for the presence of a bowel-within-bowel appearance involving the colon. The reference standard for a lead point was histopathologic examination or, if the tumor was not resected, an identifiable mass persisting on follow-up CT scans. Transient intussusception was defined as intussusception that resolved on follow-up CT scan without surgical removal or as intussusception with an intermittent presence on serial CT scans. Idiopathic intussusception was defined as the absence of mass or mural thickening at CT or surgery.

RESULTS: Four hundred sixty-one CT scan reports were retrieved, 138 of which mentioned intussusception as a pertinent negative. From the remaining 323 scan reports, after all exclusions (small bowel-small bowel intussusception, incomplete imaging, pediatric patients, and misinterpretations on rereview), 33 patients were shown to have 34 intussusceptions, including ileocolic (n = 11) and colocolic (n = 23) intussusceptions, on 34 CT scans. Seven intussusceptions were transient (i.e., intermittent). No patient had idiopathic intussusception. Histopathologic results were available for 22 of 34 intussusceptions. Intussusceptions were caused by colorectal cancer (n = 12), lymphoma (n = 5), metastases to the colon (n = 8), colon polyps (n = 4), and nonneoplastic causes, including lipoma (n = 3), hematoma (n = 1), and edema (n = 1).

CONCLUSION: In patients with cancer, intussusceptions involving the colon are never idiopathic. Most are due to primary colon cancer or metastatic disease and most require surgical removal. Although seven intussusceptions were transient, six were caused by neoplasia.