Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology Indian Medical PG Practice Questions and MCQs

Question 311: A patient presented with colon type diarrhea with blood. On sigmoidoscopy, a cauliflower mass was found and excised. On genetic analysis of the mass, which finding does NOT have prognostic value?

A. Krans (Correct Answer)
B. c-myc
C. Microsatellite instability
D. erbB2

Explanation: In colorectal carcinoma (CRC), genetic markers are used for diagnosis, screening, and predicting prognosis or treatment response. This question tests the distinction between **predictive** and **prognostic** markers. **Why K-ras is the Correct Answer:** While **K-ras** (Kirsten rat sarcoma virus) mutations are present in approximately 40% of colorectal cancers (part of the Adenoma-Carcinoma sequence), they do **not** have independent prognostic value regarding the patient's overall survival or disease progression [1]. Instead, K-ras is a **predictive marker**: its presence indicates resistance to anti-EGFR monoclonal antibody therapies (like Cetuximab and Panitumumab). **Analysis of Incorrect Options:** * **c-myc:** Overexpression of this proto-oncogene is associated with poor prognosis and aggressive tumor behavior in CRC [1]. * **Microsatellite Instability (MSI):** This is a high-yield **prognostic** marker [1]. Patients with MSI-High (MSI-H) tumors generally have a **better prognosis** and higher survival rates compared to those with Microsatellite Stable (MSS) tumors, although they respond poorly to 5-Fluorouracil [1]. * **erbB2 (HER2/neu):** Amplification of erbB2 is associated with advanced stage, increased recurrence, and overall **poor prognosis** in colorectal malignancies. **NEET-PG High-Yield Pearls:** * **Vogelstein Model:** The classic sequence is *APC* (Gatekeeper) → *K-ras* (Signaling) → *p53* (Executioner) [1]. * **MSI-H CRC:** Typically right-sided, associated with Lynch Syndrome, and characterized by "dirty necrosis" and "Crohn-like" lymphoid reaction [1]. * **Predictive vs. Prognostic:** A *prognostic* marker tells you the likely outcome of the disease; a *predictive* marker tells you how the disease will respond to a specific drug. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 819-821.

Question 312: Helicobacter pylori is associated with what percentage of gastric ulcers?

A. 10%
B. 30%
C. 50%
D. 70% (Correct Answer)

Explanation: **Explanation:** *Helicobacter pylori* is a gram-negative, spiral-shaped bacterium that plays a central role in the pathogenesis of peptic ulcer disease (PUD) [1]. It induces chronic inflammation by secreting urease and toxins (like CagA and VacA), leading to mucosal atrophy and ulceration [4]. **Why 70% is correct:** Epidemiological studies and standard pathology textbooks (Robbins) indicate that *H. pylori* infection is present in approximately **70% of gastric ulcers** [1]. In contrast, its association with **duodenal ulcers** is even higher, historically cited at **90–100%** [1]. The remaining 30% of gastric ulcers are primarily attributed to NSAID use, Zollinger-Ellison syndrome, or lifestyle factors [1]. **Analysis of Incorrect Options:** * **10% & 30%:** These figures are too low. While *H. pylori* prevalence is declining in developed nations due to better hygiene and antibiotic use, it remains the dominant cause of gastric ulcers globally. * **50%:** While a significant number, this underestimates the established correlation. 50% might represent the general prevalence of *H. pylori* in the global population, but its specific association with ulcer patients is higher [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** *H. pylori* typically causes **Antral Gastritis** (increased acid production) [1]. * **Diagnosis:** The **Urea Breath Test** is the non-invasive "gold standard" for confirming eradication. The **Rapid Urease Test (RUT)** is the invasive test of choice during endoscopy. * **Malignancy Risk:** *H. pylori* is a Class I Carcinogen associated with **Gastric Adenocarcinoma** and **MALToma** (Marginal zone B-cell lymphoma) [3]. * **Treatment:** Standard Triple Therapy includes a PPI + Amoxicillin + Clarithromycin. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 353-354. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 351-352. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 356-357. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 352-353.

Question 313: Familial polyposis coli is associated with which genetic defect?

A. MLH1
B. MSH2
C. APC (Correct Answer)
D. RET

Explanation: ### Explanation **Correct Option: C. APC** Familial Adenomatous Polyposis (FAP) is an autosomal dominant condition caused by a germline mutation in the **APC (Adenomatous Polyposis Coli)** gene located on chromosome **5q21** [1]. * **Mechanism:** The APC gene is a tumor suppressor gene that normally downregulates **Wnt signaling** by promoting the degradation of **β-catenin** [3]. * **Pathology:** When APC is mutated, β-catenin accumulates and translocates to the nucleus, triggering the proliferation of colonic epithelium [3]. This leads to the development of hundreds to thousands of adenomatous polyps [2]. Malignant transformation into colorectal carcinoma is inevitable (100% risk) by age 40-50 if the colon is not prophylactically removed. **Analysis of Incorrect Options:** * **A & B (MLH1 and MSH2):** These are **DNA Mismatch Repair (MMR)** genes. Mutations in these genes lead to **Lynch Syndrome** (Hereditary Non-Polyposis Colorectal Cancer or HNPCC) [1]. Unlike FAP, Lynch syndrome is characterized by fewer polyps and occurs via the microsatellite instability (MSI) pathway [1]. * **D (RET):** This proto-oncogene is associated with **Multiple Endocrine Neoplasia (MEN) type 2A and 2B**, as well as Familial Medullary Thyroid Carcinoma. It is not involved in colonic polyposis syndromes. **High-Yield Clinical Pearls for NEET-PG:** * **Gardner Syndrome:** FAP + Osteomas (mandible), Epidermoid cysts, and Desmoid tumors. * **Turcot Syndrome:** FAP + CNS tumors (Medulloblastoma) OR Lynch Syndrome + CNS tumors (Glioblastoma). * **Screening:** For FAP patients, annual sigmoidoscopy/colonoscopy should begin at age 10–12 years. * **Aspirin/NSAIDs:** These can cause regression of polyps in FAP by inhibiting COX-2, which is often overexpressed in adenomas. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 821-822. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 817. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 819.

Question 314: Which of the following statements is incorrect?

A. Curling ulcers are associated with severe burns.
B. Stress ulcers can be caused by shock.
C. Central nervous system lesions can lead to the formation of stress ulcers.
D. Increased prostaglandin secretion is protective against stress ulcers. (Correct Answer)

Explanation: **Explanation:** The question asks to identify the **incorrect** statement regarding stress-related mucosal disease. **Why Option D is the correct (incorrect statement) answer:** The statement is factually correct in a physiological sense, but it is the "incorrect" statement in the context of the question's logic because **decreased** (not increased) prostaglandin secretion is a primary mechanism in the pathogenesis of stress ulcers. Prostaglandins (PGE2 and PGI2) are vital for maintaining the mucosal barrier by stimulating bicarbonate and mucus secretion and increasing mucosal blood flow. In states of physiological stress, prostaglandin synthesis is inhibited, leading to mucosal injury. **Analysis of other options:** * **Option A (Correct):** **Curling ulcers** are acute gastric ulcers occurring in the proximal duodenum specifically associated with **severe burns** or trauma. * **Option B (Correct):** **Stress ulcers** are most commonly caused by physiological stress, including **shock**, sepsis, or severe systemic trauma, leading to splanchnic hypoperfusion [1]. * **Option C (Correct):** **Cushing ulcers** are gastric, duodenal, or esophageal ulcers arising in patients with **Central Nervous System (CNS)** injury or increased intracranial pressure. These are caused by vagal stimulation leading to hypersecretion of gastric acid. **NEET-PG High-Yield Pearls:** * **Mnemonic for Ulcers:** **C**urling = **B**urns (Think: "Curling" iron causes burns); **C**ushing = **C**NS (Think: "Cushing" the brain). * **Pathogenesis:** The most common cause of stress ulcers is **mucosal ischemia** (due to hypotension/shock), which reduces the protective bicarbonate layer [1]. * **Location:** Stress ulcers are usually multiple, small, and found in the stomach; Curling ulcers are often in the duodenum; Cushing ulcers have a high risk of perforation. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 353-354.

Question 315: When carcinoma of the stomach develops secondarily to pernicious anemia, it is usually situated in which region?

A. Pre-pyloric region
B. Pylorus
C. Body
D. Fundus (Correct Answer)

Explanation: The correct answer is **Fundus (Option D)**. **1. Why Fundus is correct:** Pernicious anemia is an autoimmune condition characterized by the presence of antibodies against gastric parietal cells and intrinsic factor [2]. This leads to **Autoimmune Metaplastic Atrophic Gastritis (AMAG)**. Since parietal cells are anatomically localized to the **oxyntic mucosa**, which is found in the **fundus and body** of the stomach, these are the regions that undergo chronic inflammation, mucosal atrophy, and intestinal metaplasia [1][5]. This sequence (the Correa pathway) significantly increases the risk of developing gastric adenocarcinoma specifically in these proximal regions [1]. **2. Why other options are incorrect:** * **A & B (Pre-pyloric region and Pylorus):** These areas constitute the gastric antrum. While the antrum is the most common site for *H. pylori*-associated gastric cancer, it is typically spared in autoimmune gastritis [4]. In fact, in pernicious anemia, the antrum often shows G-cell hyperplasia due to the lack of acid feedback inhibition [1]. * **C (Body):** While the body is also affected by autoimmune gastritis, the fundus is frequently cited in classic pathology literature as a primary site for malignancy arising from pernicious anemia. Between the two, the fundus represents the most proximal extent of the autoimmune destruction. **3. High-Yield Clinical Pearls for NEET-PG:** * **Type A Gastritis:** **A**utoimmune, **A**ntibodies, **A**nemia (Pernicious), and involves the **A**ndrum-sparing (Fundus/Body) [1]. * **Type B Gastritis:** **B**acterial (*H. pylori*), involves the **B**adlands (Antrum) [4]. * **Hypergastrinemia:** In pernicious anemia, achlorhydria leads to massive increases in gastrin, which can also cause **Carcinoid tumors** (Neuroendocrine tumors) due to ECL cell hyperplasia, in addition to adenocarcinoma [1]. * **Microscopic hallmark:** Loss of parietal/chief cells and replacement by mucus-secreting intestinal cells (Intestinal Metaplasia) [1][3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 770-772. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 655-656. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 592-593. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 770-771. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 350-351.

Question 316: All of the following are features of early gastric carcinoma except?

A. Mucosal involvement
B. Submucosal involvement
C. Muscularis propria not involved
D. Paradoxical aciduria (Correct Answer)

Explanation: ### Explanation **Early Gastric Carcinoma (EGC)** is defined by the depth of invasion rather than the size of the lesion, lymph node status, or clinical symptoms [1]. **1. Why "Paradoxical Aciduria" is the correct answer:** Paradoxical aciduria is a metabolic phenomenon seen in **Gastric Outlet Obstruction (GOO)**, typically due to chronic peptic ulcer disease or advanced (not early) gastric cancer. It occurs when persistent vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. To conserve volume and potassium, the kidneys eventually excrete $H^+$ ions instead of $Na^+$, leading to acidic urine despite systemic alkalosis. It is a clinical complication of advanced disease, not a pathological feature of EGC. **2. Analysis of other options:** * **A & B (Mucosal and Submucosal involvement):** By definition, EGC is a carcinoma limited to the **mucosa** and/or **submucosa** [1]. * **C (Muscularis propria not involved):** This is the defining boundary. Once the tumor penetrates the **muscularis propria**, it is classified as Advanced Gastric Carcinoma [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Definition:** EGC = Invasion limited to mucosa or submucosa, **regardless of lymph node metastasis** [1]. (Up to 10-15% of EGC cases may have positive lymph nodes). * **Prognosis:** Excellent, with a 5-year survival rate exceeding 90%. * **Classification:** Often classified using the **Japanese Endoscopic Classification** (Type I: Protruded, Type II: Superficial, Type III: Excavated). * **Most Common Site:** The lesser curvature of the antrum is the most frequent location for gastric adenocarcinoma. * **Lauren Classification:** Remember the two types—**Intestinal** (associated with H. pylori and intestinal metaplasia) and **Diffuse** (associated with CDH1 mutations and Signet ring cells). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 355-356.

Question 317: Which of the following conditions predisposes to esophageal adenocarcinoma?

A. Achalasia
B. Scleroderma (Correct Answer)
C. Corrosive intake
D. All of the above

Explanation: **Explanation:** The development of **Esophageal Adenocarcinoma** is almost exclusively linked to chronic gastrointestinal reflux disease (GERD) leading to **Barrett’s Esophagus** (intestinal metaplasia) [1]. **Why Scleroderma is correct:** In Systemic Sclerosis (Scleroderma), fibrosis of the esophageal smooth muscle leads to the loss of Lower Esophageal Sphincter (LES) tone and impaired peristalsis (the "rubber hose" esophagus). This results in severe, chronic acid reflux. This persistent irritation triggers the transformation of stratified squamous epithelium into columnar epithelium (Barrett’s), which is the direct precursor to adenocarcinoma [2]. **Analysis of Incorrect Options:** * **Achalasia (Option A):** While Achalasia increases the risk of esophageal cancer, it specifically predisposes to **Squamous Cell Carcinoma (SCC)**. This is due to the stasis of food and chronic inflammation (esophagitis) rather than acid reflux. * **Corrosive Intake (Option C):** Ingestion of lye or other corrosives causes strictures and chronic epithelial damage. Like Achalasia, this is a major risk factor for **Squamous Cell Carcinoma**, not adenocarcinoma. * **Option D:** Incorrect because the histological subtypes of cancer associated with these conditions differ. **High-Yield Pearls for NEET-PG:** * **Adenocarcinoma:** Risk factors include GERD, Barrett’s, Obesity, and Smoking. It typically occurs in the **lower third** of the esophagus [1]. * **Squamous Cell Carcinoma:** Risk factors include Alcohol, Smoking, Achalasia, Corrosive injury, and Plummer-Vinson Syndrome. It typically occurs in the **middle third**. * **Protective Factor:** Interestingly, *H. pylori* infection is associated with a *decreased* risk of esophageal adenocarcinoma due to gastric atrophy and reduced acid production. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 764-766. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 348-349.

Question 318: Which of the following is associated with an increased risk of gastric carcinomas?

A. Intestinal metaplasia (Correct Answer)
B. Gastric polyp (hyperplastic or adenomatous)
C. Atrophic gastritis
D. Corrosive antral stricture

Explanation: **Explanation:** Gastric carcinogenesis, particularly the **intestinal type** of adenocarcinoma, follows a well-defined multi-step progression known as **Correa’s Pathway** [2]. The sequence typically involves: Chronic Gastritis → Atrophic Gastritis → **Intestinal Metaplasia** → Dysplasia → Adenocarcinoma. **1. Why Intestinal Metaplasia is the Correct Answer:** Intestinal metaplasia (replacement of gastric epithelium by goblet cells and brush-border cells) is considered the most significant **pre-neoplastic precursor** for gastric cancer [2]. It represents a point of genomic instability where the mucosa adapts to chronic injury (often due to *H. pylori*), significantly increasing the risk of progression to dysplasia and malignancy. **2. Analysis of Other Options:** * **Atrophic Gastritis:** While it is a precursor in the pathway, intestinal metaplasia is a more advanced and specific histological marker of cancer risk than simple atrophy. * **Gastric Polyps:** Most gastric polyps are **hyperplastic** (inflammatory), which have negligible malignant potential. Only **adenomatous polyps** carry a significant risk (up to 30%), but they are much rarer than metaplastic changes [1]. * **Corrosive Antral Stricture:** This is a mechanical complication of ingesting caustic substances (like acids). While it causes chronic inflammation, it is not a classic established precursor for gastric adenocarcinoma. **NEET-PG High-Yield Pearls:** * **Lauren Classification:** Divides gastric cancer into **Intestinal** (associated with metaplasia, *H. pylori*, and environmental factors) and **Diffuse** (associated with *CDH1* mutations and signet ring cells; not associated with metaplasia). * **H. pylori:** The most common cause of the gastritis-metaplasia-carcinoma sequence [2]. * **Virchow’s Node:** Left supraclavicular lymphadenopathy indicating metastatic gastric cancer. * **Sister Mary Joseph Nodule:** Periumbilical metastasis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 777-778. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 354-355.

Question 319: Linitis plastica is a type of which cancer?

A. Gall bladder cancer
B. Stomach cancer (Correct Answer)
C. Pancreatic cancer
D. Renal cell cancer

Explanation: **Explanation:** **Linitis plastica** (also known as "leather bottle stomach") is a morphological variant of **Stomach cancer**, specifically associated with the **Diffuse type of Gastric Adenocarcinoma** (Lauren classification) [1]. ### Why Stomach Cancer is Correct: In this condition, the tumor cells (often **Signet ring cells**) infiltrate the submucosa and muscularis propria extensively [1]. This triggers a massive **desmoplastic reaction** (fibrosis), which causes the stomach wall to become markedly thickened, rigid, and non-distensible [1]. On gross examination, the stomach resembles a rigid leather flask or bottle, hence the name [1]. Unlike the intestinal type, it does not usually form a discrete luminal mass. ### Why Other Options are Incorrect: * **Gallbladder cancer:** Typically presents as a mass in the gallbladder fossa or wall thickening, but does not exhibit the "leather bottle" diffuse infiltrative pattern. * **Pancreatic cancer:** Usually presents as a focal mass in the head of the pancreas leading to obstructive jaundice; it does not involve the diffuse structural rigidity seen in linitis plastica. * **Renal cell cancer:** Characterized by clear cell or papillary morphology within the kidney parenchyma; it spreads via the renal vein and does not involve the gastric wall. ### NEET-PG High-Yield Pearls: * **Microscopy:** Look for **Signet ring cells** (nucleus pushed to the periphery by a large mucin vacuole) [1]. * **Genetics:** Often associated with mutations in the **CDH1 gene**, which encodes for **E-cadherin** [1]. * **Radiology:** On a Barium swallow, it presents as a narrowed, rigid stomach with a lack of peristalsis. * **Classification:** It is the hallmark of the **Diffuse type** of gastric cancer, which has a poorer prognosis compared to the Intestinal type [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 779-780.

Question 320: In which one of the following salivary gland tumors, the tumor is composed of "intermediate cells" histologically?

A. Adenoid cystic carcinoma
B. Mucoepidermoid carcinoma (Correct Answer)
C. Pleomorphic adenoma
D. Warthin's tumour

Explanation: **Explanation:** **Mucoepidermoid Carcinoma (MEC)** is the most common malignant salivary gland tumor in both adults and children [1]. Histologically, it is characterized by a unique mixture of three distinct cell types [2]: 1. **Mucus-secreting cells:** Large cells with pale, foamy cytoplasm. 2. **Squamous (Epidermoid) cells:** Cells showing polygonal shapes and occasional intercellular bridges. 3. **Intermediate cells:** These are the hallmark of MEC. They are small, basaloid cells that act as "progenitor cells," capable of differentiating into either mucous or squamous cells. **Analysis of Incorrect Options:** * **Adenoid Cystic Carcinoma:** Characterized by a "Cribriform" (Swiss-cheese) pattern [2]. It is composed of small, dark, myoepithelial and ductal cells, but lacks intermediate cells. It is notorious for perineural invasion. * **Pleomorphic Adenoma:** A benign mixed tumor showing both epithelial/myoepithelial components and a mesenchymal-like stroma (chondroid or myxoid) [3]. It does not feature intermediate cells. * **Warthin’s Tumour (Cystadenolymphoma):** Characterized by a double layer of oncocytic epithelium (pink, granular cells) forming papillary projections into cystic spaces, with a dense lymphoid stroma [1]. **NEET-PG High-Yield Pearls:** * **Most common site for MEC:** Parotid gland (though it is also the most common malignancy of minor salivary glands) [1]. * **Grading:** MEC is graded (Low, Intermediate, High) based on the proportion of these three cell types; a higher proportion of squamous and intermediate cells usually indicates a higher grade [2]. * **Molecular Marker:** Associated with the **t(11;19)** translocation, resulting in the **CRTC1-MAML2** fusion gene [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, p. 753. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 753-755. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 274-276.

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