Table 3.

Diagnostic criteria for Crohn’s disease

(1) Primary findings  A. Longitudinal ulcer (Note 1)  B. Cobblestone appearance  C. Nondysbutyroid epithelioid cell granuloma (Note 2)

(2) Secondary findings  a. Irregular or round ulcers or aphthae over a large area of the gastrointestinal tract (note 3)  b. Characteristic anal lesions (Note 4)  c. Characteristic gastric or duodenal lesions (Note 5)

Examples of a confirmed diagnosis:  1. Primary finding (A) or (B) (Note 6)  2. Primary (C) and secondary findings (a) or (b)  3. Secondary findings (a), (b), and (c)

Example of an uncertain diagnosis:  1. Primary finding (C) and secondary finding (c)  2. Primary finding (A) or (B) but the case cannot be differentiated from ulcerative colitis, intestinal Behçet’s disease, simple ulcers, or ischemic bowel lesions  3. Primary finding (C) (Note 7)  4. One or two secondary findings

Note 1: Longitudinal ulcers are observed along the long axis of the intestinal tract and have a predilection for attachment on the mesenteric side in the small intestine. These ulcers are typically 4 to 5 cm or longer; however, this length is not a required feature

Note 2: Serial sectioning improves the diagnostic yield. A pathologist familiar with the gastrointestinal tract should make the diagnosis

Note 3: Extensive involvement of the gastrointestinal tract indicates that the lesion is anatomically distributed over multiple organs, such as the upper gastrointestinal tract (esophagus, stomach, duodenum), small intestine, and large intestine. Although the lesions are typically longitudinal, they may not be in some cases. The lesion must persist for at least 3 months. Capsule endoscopic findings may indicate multiple rings on the Kerckring folds in the duodenum and small intestine. Intestinal tuberculosis, intestinal Behçet’s disease, simple ulcers, ulcers caused by nonsteroidal anti-inflammatory drugs, and infectious enteritis should be ruled out

Note 4: Characteristic anal lesions include anal fissures, cavitating ulcers, hemorrhoids, perianal abscesses, and edematous dermatomes. A proctologist familiar with Crohn’s disease should make the diagnosis

Note 5: Characteristic gastric or duodenal lesions have a bamboo knot-like appearance and notch-like depression. The diagnosis should be made by a Crohn’s disease specialist

Note 6: If only a longitudinal ulcer is present, then ischemic bowel disease or ulcerative colitis should be ruled out. If only a cobblestone appearance is present, then ischemic bowel disease or type 4 colorectal cancer should be ruled out

Note 7: Inflammatory diseases with granulomas, such as intestinal tuberculosis, should be excluded

Adapted from [1], with partial modification