Basic Science

1. What histological changes are associated with the cobblestone sign in Crohn’s disease?
   A) Transmural fibrosis and muscular hypertrophy
   B) Mucosal granulomas and transmural inflammation
   C) Lymphatic dilation and mucosal hyperplasia
   D) Serosal edema and vascular engorgementAnswer:
   B) Mucosal granulomas and transmural inflammation
   Comment: Chronic inflammation with granulomas and transmural involvement causes the alternating ulcerated and raised mucosal patterns seen in cobblestone sign (12).
   Incorrect Choices:
   • A: “Fibrosis contributes to strictures, not cobblestoning.” (15).
   • C: “Lymphatic dilation is secondary, not causative.” (14).
   • D: “Serosal changes are less prominent in cobblestoning.” (11).
2. Which cells are primarily involved in the inflammatory response leading to cobblestoning?
   A) T lymphocytes and fibroblasts
   B) Kupffer cells and macrophages
   C) Eosinophils and mast cells
   D) Neutrophils and epithelial cellsAnswer:
   A) T lymphocytes and fibroblasts
   Comment: Chronic inflammation in Crohn’s disease is mediated by T lymphocytes and fibroblasts, driving granuloma formation and tissue remodeling (15).
   Incorrect Choices:
   • B: “Kupffer cells are liver-resident macrophages, not primarily involved in intestinal Crohn’s disease.” (12).
   • C: “Eosinophils and mast cells are more involved in allergic responses.” (13).
   • D: “Neutrophils are active in acute inflammation, not chronic granulomatous inflammation.” (11).

Radiology

3. Which imaging modality best delineates the cobblestone sign in Crohn’s disease?
   A) X-ray
   B) Barium fluoroscopy
   C) CT enterography
   D) MR enterographyAnswer:
   D) MR enterography
   Comment: MR enterography offers excellent soft tissue contrast, demonstrating alternating mucosal ulcers and edematous areas characteristic of cobblestone sign (9).
   Incorrect Choices:
   • A: “X-ray lacks the resolution for identifying mucosal detail.” (3).
   • B: “Barium studies are sensitive but less precise than advanced imaging.” (7).
   • C: “CT enterography is useful but less detailed for soft tissues compared to MR.” (10).
4. What is the primary role of barium studies in identifying cobblestone sign?
   A) Diagnosing acute complications
   B) Evaluating mucosal ulceration patterns
   C) Detecting fistulas
   D) Assessing mesenteric fat involvementAnswer:
   B) Evaluating mucosal ulceration patterns
   Comment: Barium fluoroscopy highlights alternating mucosal ulceration and raised areas, which create the cobblestone appearance (4).
   Incorrect Choices:
   • A: “Barium studies are not first-line for acute complications.” (8).
   • C: “Fistulas are better assessed with cross-sectional imaging.” (6).
   • D: “Mesenteric fat is better evaluated on CT or MR.” (5).
5. What is the significance of creeping fat seen on CT in Crohn’s disease?
   A) Reflects acute inflammation
   B) Predicts fibrosis and stricture formation
   C) Indicates transmural healing
   D) Suggests abscess formationAnswer:
   B) Predicts fibrosis and stricture formation
   Comment: Creeping fat represents mesenteric fat hypertrophy, correlating with chronic inflammation and potential stricture formation (14).
   Incorrect Choices:
   • A: “Creeping fat indicates chronic inflammation, not acute.” (9).
   • C: “Transmural healing is not indicated by creeping fat.” (13).
   • D: “Abscesses are unrelated to creeping fat.” (10).

Clinical

6. What clinical symptom strongly correlates with the cobblestone sign?
   A) Acute diarrhea
   B) Chronic abdominal pain
   C) Hematemesis
   D) Recurrent tenesmusAnswer:
   B) Chronic abdominal pain
   Comment: Cobblestone sign is often associated with chronic inflammation, leading to pain and partial obstruction (17).
   Incorrect Choices:
   • A: “Acute diarrhea is less specific.” (4).
   • C: “Hematemesis is not typical of Crohn’s disease.” (5).
   • D: “Tenesmus is more related to rectal involvement.” (6).
7. What is the most common complication of cobblestone sign in Crohn’s disease?
   A) Fistula formation
   B) Toxic megacolon
   C) Small bowel obstruction
   D) Massive hemorrhageAnswer:
   C) Small bowel obstruction
   Comment: Chronic inflammation and fibrosis associated with cobblestone sign can result in strictures, leading to obstruction (13).
   Incorrect Choices:
   • A: “Fistulas are a secondary complication, less common than obstruction.” (12).
   • B: “Toxic megacolon is associated with ulcerative colitis, not Crohn’s.” (15).
   • D: “Massive hemorrhage is rare in Crohn’s disease.” (14).

References