Pitfalls in the Diagnosis of Inflammatory Bowel Disease

Robert H Riddell MDMt Sinai Hospital TorontoProf of Lab. Medicine and

PathobiologyUniversity of Toronto

Atypical gross / endoscopic distribution of disease.

Ulcerative colitis typically involves the rectumextends proximally for a variable extend often reverts to normal mucosa - abrupt or gradual.

Atypical gross / endoscopic distribution of disease.

Pitfalls in UC that mimic Crohn’s disease

Presence of a cecal or periappendiceal patch.Apparent rectal sparing

therapy - not always therapeutic enemas. usually evidence of colitis on biopsy

(some degree of architectural distortion, an excess of chronic inflammation including deep plasma cells, and neutrophils that are invariably cryptophilic).

Rectal sparingaphthoid ulcers in the transition to typical

colitic mucosa. Usually severe diseasediverticular colitis

Preparation – Oral Fleets

UC with periappendiceal patch

UC with cecal patch

Ulcers and sparing at both ends

The skip

CD mimicking UCDistribution of disease

Diffuse diseaseRectal disease

Apparent normal rectal mucosa histologicallyAb initioLongterm reversion to normal

‘gotcha’

Pitfalls - other diseasesSuperimposed infection

BacterialViral CMV

Drugs / medicationsNSAIDs

Pediatric diseaseChronic eosinophilic infiltrates (kids)

Churg-StrausChronic allergic colitis

Atypical CD-like (young +/- severe UGI disease)DiversionPouchitis

Rectal stump post colectomy –Is it Crohn’s? Take 2 Rectal Bx

Diversion disease / diversion proctitisClassically mucosal lymphoid hyperplasia BUTCan look focal with aphthoid ulcers or diffuseCan have granulomas Can be diffuse with crypt abscessesIf resected can have Crohn’s like transmural lymphoid hyperplasia

Therefore Can mimic CD or UCTherefore DON’T ASK!!! Once it is established we can’t tell you.

Once established it is always Diversion disease

Pouchitis + Fistula. Is it CD?Pouchitis

Classically is Crohn’s-likeCan look focal with aphthoid ulcersCan have granulomasIf resected can have Crohn’s like transmural lymphoid hyperplasia

Therefore Can mimic UC or CDTherefore DON’T ASK!!! We can’t tell you.

It is always PouchitisPossible exception – pre-pouch ileitis with skip

Can mimic CD and may respond to RemicadeDoes that make it CD?

Upper GI diseaseEstablished in CD

Focal chronic active Hp neg gastritisHp neg erosionsGranulomas ? Mild superficial chronic gastritis

Severe UC - esp childrenActive duodenitis (bulb)? Chronic Hp neg gastritisResolves post Rx / Colectomy

Crohn’s disease - pitfalls

Other causes of focal disease:Biopsy of inflammatory polypsBiopsy of granulation tissue at anastomotic lines

Inflammatory kick in cecal biopsies (normal) or in UCOvercalling normal terminal ileal lymphoid aggregates as inflamedFulminant colitis of any cause – including UC (aphthoid ulcers, rectal sparing)

Why are there problems?The pathologist does not know or understanding the reasons why the biopsies were taken

question or reason biopsies taken not stated. (Can’t answer a question if there isn’t one)

Pathologist is unaware of criteria (“NSp inflammation”)CME courses,web,crack a book,ask

The endoscopist is unaware of what biopsies are needed to answer the questions that has been specifically asked

know the criteria used to make the diagnoses take the appropriate biopsies to answer the Qu

The question being asked cannot be answered at all using biopsies

know when pathology cannot answer the question

“You never give me what I need”

“But Honeyyou never tell mewhat you want”

Pitfalls in Bx in IBDDistribution or focality not demonstrated

The occasional biopsyAll in one container

Cecal Bx (MC-like) / cecal patch misinterpretedIdentify separately

Mucin granulomas (and giant cells)Focality post Rx – how much is allowed?

Rarely erosionsApparent rectal sparing or proximal limit

Demonstrate it “Normal” biopsies histologically and implications

Ab initioAcquired/repair

Abnormal endo – Looks like CD. Is it?

Have to demonstrate the distribution and focalityErosions / Aphthoid ulcers / Edges of ulcers

Usually on background of focal inflammationCrypt sparing<5% CD is really diffuseRare in UC (highly asymmetric healing)

PitfallsMimics of aphthoid ulcers

Biopsies from Inflammatory polypsAnastomotic linesInfections with focal ulcersPreparation artefact

Pitfalls in SurveillanceUnderstand its limitationsDon’t repeat the colonoscopy to “confirm the diagnosis”Better methods of surveillance

Chromoscopy + Magnification endoscopyAutofluorescence

Carcinomas arise from any grade of dysplasiaUnderstand the algorithm for adenomas in colitic mucosa v. DALM

Pitfalls in SurveillanceLength 100 cm Circumference 10cm Area 1000cm2

1cm

2cm

needs 1000/3.14 equally spaced biopsies - c.320 biopsies

Area =πr2 = 3.14cm2

33 Bx for 90% of finding dysplasia if present

(55 for 95%) (Rubin 1992 - artificial)

03-16254Singh.jpgM52 20y Hx UC 1cm Polyp in Sigmoid

03-16254Singh.jpgM52 20y Hx UC 1cm Polyp in Sigmoid

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03-16254Singh4.jpg

The big mythThe big myth

No/minNo/min LowLow--gradegrade HighHigh--gradegrade IncipientIncipientdysplasiadysplasia dysplasiadysplasia dysplasiadysplasia invasioninvasion

Invasive Ca

How it really worksHow it really works

No/minNo/min LowLow--gradegrade HighHigh--gradegrade IncipientIncipientdysplasiadysplasia dysplasiadysplasia dysplasiadysplasia invasioninvasion

Invasive Ca

Other“Non-dysplastic”

pathways

In colitic mucosa:Is it an adenoma or a DALM?Adenoma (local excision)Dysplasia Associated Lesion or Mass (DALM) (colectomy) – more widespread or atypical ?CaIf it looks like an adenoma

(Adenoma-Like Mass – Bernstein)Excise endoscpically – good stalk if possible to demonstrate complete excisionBiopsy around base to ensure completeRoutine surveillance runIf excised and rest negative can Rx as AdBeware atypical lesion + any histological dysplasia

03-2184 3-8AdinUC.jpg

03-2184 3-8AdinUC-2Arch.jpg

03-2184 3-5 DALM-1.jpg

03-2184 3-5 DALM-2.jpg

Other Pitfalls?The pathologist needs to understand the question or reasons the biopsies were takenPathologist needs to know their stuff

(No “Non-specific inflammation”)The endoscopist must be aware of what biopsies are needed to answer their questions

Needs to know their stuffKnow when pathology cannot answer the question or the limitations

“How about meeting over that hot

little scope of yours”

“MmmmmYours or mine?”