Spectrum of histopathological changes encountered in stented colorectal carcinomas

Aims 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. Methods and results 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. Conclusions 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.