Digestive System II – Pathology Review

These flashcards cover key entities, risk factors, morphologic features, and classifications of esophageal, gastric, small- and large-bowel pathology discussed in the lecture ‘Digestive System II – Pathology.’

What pathologic change characterizes Barrett’s esophagus?

Intestinal (columnar) metaplasia within the esophageal squamous mucosa.

Barrett’s esophagus confers an increased risk for developing which malignancy?

Esophageal adenocarcinoma.

Approximately what percentage of individuals with Barrett’s esophagus develop dysplasia each year?

About 0.2 % – 1 % annually.

Which two findings are required to diagnose Barrett’s esophagus?

(1) Columnar-type mucosa in the distal esophagus on endoscopy; (2) Specialized intestinal metaplasia on histology.

List the progressive stages from reflux injury to cancer in Barrett’s esophagus.

Esophagitis → Barrett’s esophagus without dysplasia → Low-grade dysplasia → High-grade dysplasia → Adenocarcinoma.

Esophageal adenocarcinoma typically arises in the setting of which pre-existing condition?

Barrett’s esophagus with long-standing GERD.

Name three established risk factors for esophageal adenocarcinoma other than GERD.

Tobacco use, obesity, previous mediastinal radiation therapy.

Which population is most frequently affected by esophageal adenocarcinoma?

White males (≈ 7 : 1 male-to-female ratio).

Where in the esophagus does adenocarcinoma most commonly occur?

Distal third of the esophagus.

Microscopically, esophageal adenocarcinomas usually produce and form .

Produce mucin and form glands.

At what age group does esophageal squamous cell carcinoma (SCC) usually present?

Adults older than 45 years.

Name four key risk factors for esophageal squamous cell carcinoma.

Alcohol use, tobacco use, caustic esophageal injury, achalasia (others: poverty, very hot beverages, Plummer-Vinson syndrome, prior radiation).

Which racial group has the highest incidence of esophageal SCC?

African Americans (≈ 6× more common than in Whites).

In which anatomic third of the esophagus does SCC most often arise?

Middle third.

Describe the early and late gross appearance of esophageal SCC.

Early: small gray-white plaque-like thickenings; Late: polypoid/ulcerated masses causing luminal obstruction or diffuse wall thickening.

Define Peptic Ulcer Disease (PUD).

Chronic ulceration of gastrointestinal mucosa due to increased gastric acidity and/or impaired mucosal defense.

Give two major etiologic factors for PUD.

Helicobacter pylori infection and parietal-cell hyperplasia (others: excessive acid secretion, impaired inhibition of gastrin).

List three important risk cofactors that exacerbate PUD.

NSAID use (or high-dose corticosteroids), tobacco use, alcohol use (others: chronic renal failure, hyperparathyroidism).

What is the classic gross morphology of a peptic ulcer?

Round-to-oval, sharply punched-out defect with a smooth, clean base of richly vascular granulation tissue.

What proportion of gastric polyps are hyperplastic?

Approximately 75 %.

Hyperplastic gastric polyps usually arise in the setting of which underlying condition?

Chronic gastritis causing mucosal injury and reactive hyperplasia.

Fundic gland polyps may occur sporadically or in association with which hereditary syndrome?

Familial adenomatous polyposis (FAP).

Do fundic gland polyps carry significant malignant potential?

No; they generally lack neoplastic potential.

Gastric adenomas (≈ 10 % of gastric polyps) typically arise on a background of and .

Chronic gastritis with atrophy and intestinal metaplasia.

List three etiologic associations for gastric adenocarcinoma.

Genetic mutations, chronic H. pylori gastritis, Epstein–Barr virus infection.

What term describes the diffusely infiltrative, rigid ‘leather-bottle’ stomach seen in some gastric cancers?

Linitis plastica.

From which cell type do Gastrointestinal Stromal Tumors (GISTs) originate?

Interstitial cells of Cajal (GI pacemaker cells).

Name the three microscopic patterns of GIST.

Spindle type (~70 %), epithelioid type (~20 %), mixed type (~10 %).

Describe the spindle-cell morphology of a GIST.

Bland spindle cells with faintly eosinophilic cytoplasm in syncytial sheets, elongated nuclei, inconspicuous nucleoli, and paranuclear vacuoles (especially in gastric GIST).

What triad characterizes Peutz-Jeghers syndrome?

Autosomal dominant inheritance, multiple GI hamartomatous polyps, mucocutaneous hyperpigmentation.

Peutz-Jeghers syndrome increases the risk of malignancy in which organs (name three)?

Colon, pancreas, breast (also lung, ovaries, uterus, testes).

What is Familial Adenomatous Polyposis (FAP)?

An autosomal dominant syndrome with hundreds to thousands of colorectal adenomatous polyps and near-certain progression to carcinoma without prophylactic colectomy.

By definition, all colorectal adenomas must show which histologic feature?

Epithelial dysplasia.

Differentiate tubular, tubulovillous, and villous adenomas by villous architecture percentage.

Tubular < 25 % villous; Tubulovillous 25–75 % villous; Villous > 75 % villous.

What is the most common malignant tumor of the large bowel?

Colorectal adenocarcinoma (> 95 % of colorectal cancers).

Contrast the gross appearance of right-sided versus left-sided colorectal adenocarcinomas.

Right colon – polypoid/exophytic masses; Left colon – annular ‘napkin-ring’ constricting lesions that may obstruct.

List four key microscopic features of colorectal adenocarcinoma.

Infiltrating glands, desmoplastic stroma, nuclear atypia (hyperchromatic, stratified), possible dirty necrosis within lumens.

Name three special histologic subtypes of colorectal adenocarcinoma and their prognostic significance.

Mucinous (> 50 % mucin, worse prognosis); Signet-ring cell (aggressive, diffusely infiltrative); Medullary (solid, MSI-associated).

How is colorectal adenocarcinoma graded histologically?

Well-, moderately-, and poorly differentiated based on gland formation.

Where are large-bowel neuroendocrine (carcinoid) tumors most commonly found, and what is their classic histology?

Appendix or rectum; nests/cords of uniform cells with ‘salt-and-pepper’ chromatin.

Which lymphoma type is most common in the colon?

Diffuse large B-cell lymphoma.

GISTs are very rare in the colon; histologically they consist of or cells arranged in whorls or fascicles.

Spindle or epithelioid cells.

Name the four major tissue origins used to classify small-bowel neoplasms.

Epithelial, endocrine (neuroendocrine), mesenchymal, and lymphoid origins.