Pathology in the selection of patients for pouch surgery. Dr Bryan F Warren Consultant Gastrointestinal Pathologist, Honorary Senior Lecturer, Fellow of Linacre College, Oxford M62 Course 2006

Pathology in pouch surgery One stage Two stage Three stage

One stage-Communication and context What do I tell the pathologist?

Biopsy – severe UC Crypts rupture downwards to involve superficial submucosa Mimic CD Distribution and context!

Biopsy pathology UC Crypt architectural distortion takes 6 weeks Diffuse changes- Architecture, mucin depletion, chronic inflammation, acute inflammation Rectum most severe Distribution of changes in a biopsy and in a biopsy series. Catch-patchiness-post treatment or at junction of diseased and normal, or in caecal patch. IF BIOPSIES ALL IN SAME POT - HARD TO REPORT!! Early disease-diffuse Chronic inflammation and basal plasma cells UC after treatment

Crohn’s colitis Schiller KFR, Cockel R, Hunt RH, Warren BF An atlas of gastrointestinal endoscopy and related pathology

Crohn’s colitis Focal erosions and Focal inflammation Perineural chronic inflammation and granuloma. Aphthous ulcer Granuloma in relation to ruptured crypt-not all CD

Cryptolytic granulomas Lee FD, Maguire C, Obeiat W, Russell RI. Importance of cryptolytic granulomas in inflammatory bowel disease. J Clin Pathol 1997;50: patients with non specific inflammatory changes and pericryptal granulomas on biopsy 10 were found to have Crohn’s disease

Quiescent/ treated UC May have only architectural distortion, =/-paneth cells, may return to ‘normal’-review original biopsies ? Infection. Polyp Flat mucosa `patchy mimics CD Rectal sparing DON’T JUST BIOPSY THE POLYP

Follow up/ post treatment biopsies in IBD Is it still IBD/UC/Crohn’s disease Has it got better? Was it IBD after all? Is it now complicated by infection/PMC? Go back to the original pretreatment series!

Crohn’s large bowel biopsy. May be normal May mimic UC Patchiness is most reproducible feature Mucosal granulomas – may mislead

Pathology in pouch surgery Two stage and three stage Colectomy! Three stage –Colectomy –Rectal stump

Crohn’s disease - fat wrapping

Crohn’s colitis Transmural inflammation in the form of lymphoid aggregates The pathologist cannot see this on a biopsy - help him - context

Crohn’s colitis-terminal ileal disease. Backwash ileitis in UC or Crohn’s disease? Ileal biopsies may be difficult.

Biopsies after surgery Ileostomy end - non specific changes may misinterpret as Crohn’s disease Anastomotic biopsies in Crohn’s Diversion –CD may mimic UC –UC may mimic CD

Diversion in UC Transmural inflammation Granulomas PMC like change Mimics Crohn’s It is UC and not a contraindication to pouch surgery. Seen as part of the three stage pouch procedure. Comforting if this occurs-helps confirm pouch has been made in UC! PUT THE BIOPSIES IN CONTEXT FOR THE PATHOLOGIST!

Diverted Crohn’s colitis

When is it difficult to differentiate CD colitis and UC? Fulminant colitis After treatment of UC When rare variants of UC are not recognised.

Skip lesions in UC Acceptable ones: Appendix –Davison and Dixon Caecal patch – D‘Haens Not contraindications to pouch surgery.

Caecal patch in UC Courtesy of Dr Axel von Herbay Tell the pathologist What you saw Please label biopsy Sites Not all in same pot!

Indeterminate or unable to tell for the wrong reasons? Referral to an expert! Pass on/ share the decision making - good but… Biopsies minus information Resection - must be easy, histology must give all the answers! Photo -absent/poor Macroscopic description - length of colon only Slides four from unknown sites around the colon Remains undiagnosable - not true indeterminate

Working Party clinical classification Indeterminate Colitis: use and abuse controversies and consensus (WCOG) Séverine Vermeire, MD, PhD (Leuven, Belgium) Robert Riddell, MD, PhD (Toronto, Canada) Bryan Warren, FRCPath(Oxford, UK) Karel Geboes, MD, PhD (Leuven, Belgium)

Introduction Population-based studies from Scandinavia showed that 5-20% of IBD patients affected by colonic involvement only cannot be definitively diagnosed with CD or UC using available diagnostic tools  indeterminate colitis (IC) Incidence of IC estimated at / What are they calling “IC” Moum Gut 1997, Hildebrand J Pedriatr Gastroenterol Nutr 1991, Stewenius Scand J Gastroenterol 1995

Definition of IC: evolution of diagnostic criteria 1978: introduction of ‘colitis indeterminate’ by Ashley Price (J Clin Pathol 1978) based on surgical specimens features of both CD and UC Wide-spread use of endoscopy and biopsies evolution towards diagnosis based on clinical features + endoscopy +Bx clinical features of chronic IBD, without small bowel involvement; endoscopy non- conclusive ;microscopy active-patchy chronic inflammation with crypt distortion (>10%) and absence of diagnostic features for CD or UC ………………………………………… IC = Temporary diagnosis Majority of patients prove to have either CD or UC during follow up Is IC distinct disease within IBD?

Data from epidemiological observations in patients with IC (Stewenius et al J Eur J Surg 1996; McIntyre et al Dis Colon Rectum 1995; Atkinson et al Am J Surg 1994; Stewenius et al Dis Colon Rectum 1996; Stewenius et al Int J Colorectal Dis 1995) –clinical course –Prognosis CD, UC or IC: does it matter? worse compared to UC, especially concerning risk for and outcome of surgery “Can I do a pouch?” Conflicting data (Dayton Mt 2002, Wells AD 1991, Brown CJ 2005)) –patients operated at St Mark’s London ( ), with diagnosis of IC performed well and were unlikely to develop CD –Toronto: although greater risk for pouchitis in IC (43%) vs UC (21%), no increased risk for pouch failure with excision (10% vs 6%)

Proposed classification for patients with chronic inflammatory colitis Diagnosis based on surgical specimen Diagnosis based on endoscopy with biopsies chronic IBD with inflammation restricted to colon and no small bowel involvement. non-conclusive endoscopy microscopy: active patchy chronic inflammation with minimal or moderate architectural distortion and no diagnostic features for CD or UC. No infectious colitis overlapping features of both CD and UC indeterminate colitis Upper GI evaluation (G-scope, double balloon and/or videocapsule) useful Colonic IBD Type Unclassified (IBDU)

Summary - Pathology in the selection of patients for pouch surgery. Biopsies and resections considered in CONTEXT Awareness of rare variants and effects of treatment Consistent use of terminology Multidisciplinary team approach