Doudenum

Histopathological diagnosis of gluten sensitive entropathy

Although Biopsy Examination is gold standard, A pathologist doesn't make the diagnosis, only can say …. Abnormalities are consistent with CD

Even in centers with a high interest in CD, 12% of Biopsy specimens are not suitable So the diagnosis is impossible

Steps for better evaluation:

* 4 to 5 biopsies open cup diameter (4-6mm)

* Fallowing sites: Duodenojejunal flexure at the level of ligamentum treitz and/or Distal transverse portion of duodenvm (D3) Descending duodenum distal to the papilla of vater (D2) Descending duodenum proximal to the papilla of vater (D1) Duodenal bulb (B)

* Orient the sample adequately on a small piece of paper

Embeding the specinens on edge in paraffin wax, for serial transverse (3-4 µ m) sections and H&E staining

Identification of four villi in a row considered as adequate.

Mucosal lesions: (modified marsh classification) Type O: the preinfiltrative lesion (normal) Minimal mucosal changes not detectable with conventional light microscopy Type I: the infiltrative lesion (IEL, at least 40/100 entrocytes & at the top) *** In iran (upper limit of normal IEL 37/100 in HE, 39/100 in IHC) Type II: hyperplastic (crypt elongation, budding,  mitoses) Type III (a,b,c): destructive lesion  classic CD lesion (a)  mild atrophy (V/c ≤ 2:1) (b)  moderate atrophy (V/c ≤ 1:1) (c)  sever atrophy Type IV: flat mucosa

Immunohistochemical studies isnot part of routine analysis,  IHC can help in appreciating the extent and distribution of lymphocytic exocytosis & CD markers

Immunostainging of IELs ●  TCR γδ + ● 70% CD 8+ ● 10% CD 4+ ● 20% CD 3+ ● Variable CD 103+

Histologic response to gluten free diet ● varies from patient to patient ●  IEL and mitoses as little as one week ● beginning return of villi height at least 3 months ● after 1 to 2 years on a strict diet v/c ratio may be near normal ● reappearance of histologic changes after re-exposure varies from 2 hours to 6 days.

INTESTINAL BIOPSIES SUB-TOTAL VILLOUS ATROPHY NORMAL MUCOSA TGA positive TGA negative AEA positive AEA negative AEA positive AEA negative AEA positive AEA negative AEA positive AEA negative Probabilities of Biopsy and Antibodies Situations

* Approximately 25% of patients with CS who have also had colonic Biopsy lymphocytic colitis * 15% of patients with lymphocytic colitis who have had duodenal biopsy CS

Differential diagnosis (Abnormal histologic patterns)

1.Entities usually associated with a diffuse severe villus abnormality and crypt hyperplasia A. Celiac sprue B. Refractory or unclassified sprue C. Other protein allergies D. Lymphocytic enterocolitis

II. Entities usually associated with a variable villus abnormality and crypt hypoplasia A. Kwashiorkor, malnutrition B. Megaloblastic anemia C. Radiation and chemotherapeutic effect D. Microvillus inclusion disease

III. Entities usually associated with a nonspecific variable villus abnormality, usually not flat A.Changes associated with dermatitis herpetiformis B.Partially treated or clinically latent celiac sprue C.Infection D.Stasis E.Tropical sprue F.Zollinger-Ellison syndrome G.Mastocytosis H.Nonspecific duodenitis I.Autoimmune enteropathy J.Torkelson syndrome

IV. Entities associated with variable villus abnormalities illustrating specific diagnostic changes A.Common variable immunodeficiency B.Whipple’s disease C.Mycobacterium avium-intracellulare complex infection D.Eosinophilic gastroenteritis E.Intestinal lymphoma F.Parasitic infestation G.Waldenstrom’s macroglobulinemia H.Lymphangiectasia I.Enteropathy-associated T-cell lymphoma

Potential pitfals: ● Tangenitally cut sections ● Superficial biopsies inthout muscularis mucosa ● Villi adjacent to lymphoid follicles * Any evidence of brunner ’ s glands, gastric metaplasia, duodernitis  Sample should be disregarded and repeated more distally.