Acute and Chronic Colitis an approach to biopsy interpretation

Bernhard Stamm, Zürich

stamm.bernhard@gmail.com

Endoscopist‘s questions

• Normal mucosa?

• If inflammation, self-limiting or of longer

duration?

• Any clue to etiology?

• Could it be IBD?

• Histological diagnosis based on a limited

set of mostly ambiguous mucosal

response patterns

Need of structured approach

Artefact or disease?

• Artefacts may interfere with a diagnosis of

inflammation

- Edema - density of mononuclear cells - epithelial flattening - mucin depletion - few focal neutrophils

are weak arguments for genuine inflammation

„exclusion biopsies“

• „Mild chronic non-specific inflammation“

may be misleading

In case of doupt better:

• „Minor changes, possibly artefacts“

If obvious colitis..

• Acute or chronic?

• or any of the more specific histological

patterns, likely to contribute to the clinical

workup?

Acute colitis „self-limiting“ preserved crypt architecture predominantly neutrophils epithelial damage

Chronic colitis diffuse distortion of crypt architecture predominantly mononuclear cells Paneth metaplasia

Natura non facit saltus Woman, 29 bloody diarrhea, five weeks

Pattern recognition

beside acute and chronic

Microscopic colitis

Pseudomembranous

colitis

„volcano-like“ exudate of

neutrophils and mucin

Acute ischemia

„ischemic colitis“

superficial necrosis and

hemorrhage

crypt atrophy

eosinophilic hyalinization of

lamina propria

Entero-hemorrhagic E.coli –epidemic in Southern Germany Man, 40 severe bloody diarrhea

• Other patterns: focal active colitis,

eosinophilic colitis, granulomatous

colitis.....

• Evaluation of patterns best at low

magnification!

Two additional questions always to

be kept in mind..

• Histological recognizable microorganisms?

• Adverse effect of drugs?

Intestinal spirochaetosis

Man, 39, two years history of UC

steroid-resistant relapse, necessitating colectomy

• Tourism

• Migration

• Immunosuppression

Tourism Man, 40 Flight attendant chronic diarrhea

Immigration Mendrisio reception center for asylum seekers 2004 – 2016 of 103 patients with active tuberculosis - 27 with extrapulmonary manifestations Swiss Medical Forum 2018;18:844

Immunosuppression

Man, 35, HIV infection, chronic diarrhea Cryptosporidiosis

Could it be drug related?

• Wide and for general pathologists

somehow frustrating chapter

• Any form of colo-rectal inflammation

possible

• Very few drug-specific histological patterns

Increasing likeliness of drug related

injury

• Otherwise unexplained colitis

• Unusual clinical / morphologic aspects

• Temporal coincidence

• Drug with well documented adverse

effects

• subtle histological hints (eosinophilia,

„bland“ ulcerations, increased apoptotic

activity....)

Man, 62, Anti PD-1 therapy for laryngeal carcinoma Severe diarrhea Lymphocytic expansion of the lamina propria Crypt drop out Epithelial lymphocytosis Chen JH et al. Am J Surg Pathol 2017;41:643 (8 patients)

Apoptosis

Idiopathic inflammatory bowel

disease

• Any colitis of more than 4 weeks duration

invariably raises the question of IBD

Ulcerative colitis

typically begins in the

rectum and extends

proximally

primarily a mucosal

inflammation

No spared segments

No thickening of the wall

No strictures

Crypt architectural

distortion

basal plasma cells

activity (variable)

Crohn‘s disease

in contrast to UC:

- segmental

- transmural

- rectal sparing

- ileal involvement

Patchy distribution

extension into the

submucosa

(granulomas)

Biopsy diagnosis

difficult, if isolated

Crohn‘s colitis

IBD-definition

• An idiopathic and chronic intestinal

inflammation

• manifesting as ulcerative colitis or Crohn‘s

disease

It follows that...

• final diagnosis requires correlation with

clinical findings

• the contribution of pathology is critical but

not entirely conclusive

How far can biopsy diagnosis go?

• Depends also on..

• Quality, number and localisation of

biopsies (esp. separate rectal biopsies)?

• Clinical context provided (previous

treatment, suspected infection, drugs)?

„Formulation proposals“

• No evidence of chronic colitis

• IBD must be considered

• possibly IBD

• consistent with IBD

• probable IBD

• characteristic of IBD

• highly suggestive of IBD

Further information/comments

expected from the pathologist

• UC or CD?

• Activity of the inflammatory process?

• Coexisting conditions or complications

(esp. dysplasia, CMV)?

Mimics

• Diverticular disease associated colitis

• Diversion colitis

• Drug induced chronic colitis

• Infection

• ...

• Clinical context!

man, 51 Bloody discharge since several weeks rectal ulcers

Diffuse mild crypt distortion dense transmucosal infiltrate with mononuclear predominance Chlamydia trachomatis Serovar L2