ABPath Gastrointestinal Pathology 1 — Questions and Answers
Question 1: Barrett esophagus is defined histologically by the presence of which type of metaplasia?
- Gastric fundic metaplasia
- Squamous metaplasia
- Intestinal metaplasia with goblet cells (Correct answer)
- Pseudostratified columnar metaplasia
Correct answer: Intestinal metaplasia with goblet cells
Barrett esophagus requires intestinal metaplasia with goblet cells in the distal esophagus, confirmed by Alcian blue stain at pH 2.5.
Question 2: Helicobacter pylori preferentially colonizes which region of the stomach?
- Fundus
- Cardia
- Antrum (Correct answer)
- Greater curvature body
Correct answer: Antrum
H. pylori colonizes the gastric antrum preferentially, where it is detected by Giemsa, Warthin-Starry silver stain, or CLO (rapid urease) test.
Question 3: Which histologic feature BEST distinguishes Crohn disease from ulcerative colitis?
- Crypt abscesses
- Goblet cell depletion
- Transmural inflammation with granulomas (Correct answer)
- Mucosal ulceration
Correct answer: Transmural inflammation with granulomas
Transmural inflammation with non-caseating granulomas is the hallmark of Crohn disease, whereas ulcerative colitis is limited to the mucosa and submucosa.
Question 4: Hirschsprung disease results from absence of ganglion cells in which layer of the bowel wall?
- Muscularis mucosae
- Submucosal (Meissner) and myenteric (Auerbach) plexuses (Correct answer)
- Lamina propria
- Serosa
Correct answer: Submucosal (Meissner) and myenteric (Auerbach) plexuses
Hirschsprung disease results from failed neural crest cell migration, causing absence of ganglion cells in the submucosal and myenteric plexuses of the rectosigmoid.
Question 5: A villous adenoma of the rectum is associated with highest risk for malignant transformation compared to other polyp types because it has:
- Highest density of goblet cells
- Largest surface area with maximal dysplasia exposure (Correct answer)
- Submucosal invasion at presentation
- Microsatellite instability
Correct answer: Largest surface area with maximal dysplasia exposure
Villous adenomas have the greatest malignant potential (up to 40%) due to their larger size, greater surface area, and higher degree of dysplasia at diagnosis.
Question 6: Lynch syndrome (hereditary non-polyposis colorectal cancer) is caused by germline mutations in which genes?
- APC and MUTYH
- MLH1, MSH2, MSH6, PMS2 (MMR genes) (Correct answer)
- BRCA1 and BRCA2
- SMAD4 and BMPR1A
Correct answer: MLH1, MSH2, MSH6, PMS2 (MMR genes)
Lynch syndrome results from germline mutations in DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS2), leading to microsatellite instability.
ABPath Gastrointestinal Pathology 1
Barrett esophagus is defined histologically by the presence of which type of metaplasia?