Table 4: Histopathologic classification of CD based on Marsh-Oberhuber [56, 57], and Corazza and Villanacci [58] new grading system [12, 57, 59].

Marsh-Oberhuber classification

(i) Marsh I: infiltrative lesion, normal villous architecture and mucosa, and IEL increase (>30–40 lymphocytes/enterocytes counted).
(ii) Marsh II: hyperplasic lesion; similar to Marsh I with crypt hyperplasia.
(iii) Marsh III: destructive lesion, subdivided to the following:
 (a) partial villous atrophy,
 (b) subtotal villous atrophy,
 (c) total villous atrophy.

New grading system

(i) Grade A (nonatrophic): >25 IELs/100 enterocytes.
(ii) Grade B (atrophic): villous-crypt ratio <3 : 1.
(iii) Grade B2 (atrophic): no detectable villi.