Spectrum of histopathological changes encountered in stented colorectal carcinomas

Self-expanding metallic stents (SEMS) are increasingly being used in obstructing colorectal cancer (CRC) as a 'bridge to surgery', allowing conversion of potentially high-risk emergency resections to elective procedures. Stenting may cause a wide array of histological changes. We present the largest series to date of stented CRC, performed and reported at a single institution.

Stented CRC specimens received in January 2006 to December 2011 were identified from our pathology database. Slides for each case were independently reviewed by two pathologists, and a consensus was reached. A total of 72 CRCs were identified, 15 at or proximal to the splenic flexure, and 57 left-sided. Thirty-six were stage pT3 and 36 were stage pT4. Perforation was observed in 14 cases. The effects of stenting on the tumour included tumour necrosis (100%) and flat ulceration (77.8%). The spectrum of changes in the background bowel included mimics of inflammatory bowel disease, tumour regression post-neoadjuvant therapy, and ischaemia.

Given the inclusion of stenting of CRC as a bridge to surgery in the current NICE guidelines, we expect to see increasing numbers of such cases. In our study, a range of changes were encountered that mimic other bowel diseases, from simple fissuring to chronic inflammatory bowel disease and neoadjuvant regression change.