Gastrointestinal Pathology — MCQs

A 54-year-old woman presents with complaints of abdominal fullness and early satiety. She denies a change in bowel habits and states that constipation is her normal state. A radiographic bowel series shows an 'apple core' lesion in her sigmoid colon. Which of the following markers is expected to be elevated in this patient?

Q365Easy

Toxic megacolon is seen as a complication in which of the following conditions?

Q366Medium

Which of the following is NOT considered a high-grade salivary gland malignancy?

Q367Easy

Helicobacter pylori infection is associated with which type of gastritis?

Q368Easy

What is the most common extranodal site for non-Hodgkin's lymphoma?

Q369Easy

A Mallory-Weiss tear occurs at which anatomical location?

Q370Medium

A 68-year-old man has had "heartburn" and substernal pain after meals for 25 years. For the past year, he has had increased pain with difficulty swallowing both liquids and solids. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows an ulcerated lower esophageal mass that nearly occludes the lumen of the esophagus. A biopsy specimen of this mass is most likely to show which of the following neoplasms?

Gastrointestinal Pathology Indian Medical PG Practice Questions and MCQs

Question 361: A 50-year-old male presents with obstructive symptoms. Biopsy of the stomach reveals a Gastrointestinal stromal tumor (GIST). What is the most appropriate marker for GIST?

A. CD 34
B. CD 117 (Correct Answer)
C. CD 30
D. CD 10

Explanation: **Explanation:** **Gastrointestinal Stromal Tumor (GIST)** is the most common mesenchymal tumor of the gastrointestinal tract, most frequently occurring in the stomach. These tumors originate from the **Interstitial Cells of Cajal (ICC)**, which serve as the GI pacemaker cells. **Why CD 117 is the Correct Answer:** Approximately 95% of GISTs are positive for **CD 117**, which is the protein product of the **c-KIT proto-oncogene**. This gene encodes a transmembrane receptor tyrosine kinase. Mutations in c-KIT lead to constitutive activation of the kinase, driving tumor cell proliferation. CD 117 is considered the "gold standard" diagnostic marker and is essential for initiating targeted therapy with **Imatinib** (a tyrosine kinase inhibitor). **Analysis of Incorrect Options:** * **CD 34:** While positive in about 70% of GIST cases, it is less specific than CD 117 and is also expressed in various other mesenchymal tumors (e.g., Solitary Fibrous Tumor). * **CD 30:** This is a marker for Reed-Sternberg cells in Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma (ALCL). * **CD 10:** Also known as CALLA, it is primarily used as a marker for Acute Lymphoblastic Leukemia (ALL) and certain renal/endometrial tumors. **High-Yield Facts for NEET-PG:** * **DOG1 (Discovered On GIST 1):** This is a highly sensitive and specific marker, often positive even in CD 117-negative GISTs. * **Genetics:** Most GISTs have **c-KIT** mutations; a subset (especially gastric GISTs) may have **PDGFRA** mutations [1]. * **Histology:** Most common pattern is **Spindle cell** (70%), followed by Epithelioid. * **Staining:** GIST is typically negative for Desmin and S100 (helping differentiate it from Leiomyoma and Schwannoma). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 782-783.

Question 362: What is the most common site of squamous cell carcinoma of the esophagus?

A. Upper third
B. Middle third (Correct Answer)
C. Lower third
D. Cardia

Explanation: **Explanation:** The esophagus is anatomically divided into three segments, and the distribution of malignancies varies significantly based on the histological type. **1. Why the Middle Third is Correct:** Historically and globally, **Squamous Cell Carcinoma (SCC)** is the most common histological type of esophageal cancer. Epidemiological studies and pathology textbooks (such as Robbins) consistently identify the **middle third (50%)** as the most frequent site for SCC, followed by the lower third (30%) and the upper third (20%) [1]. This predilection is attributed to the prolonged contact of carcinogens (tobacco, alcohol, and hot liquids) at the physiological points of narrowing within the mid-esophagus. **2. Analysis of Incorrect Options:** * **Upper Third (A):** While SCC can occur here, it is the least common site (approx. 20%). It is often associated with Plummer-Vinson syndrome. * **Lower Third (C):** This is the most common site for **Adenocarcinoma**, which typically arises from Barrett’s esophagus (metaplasia due to chronic GERD). While SCC can occur here (30%), it is not the *most* common site for SCC. * **Cardia (D):** This is the junction between the esophagus and stomach. Tumors here are almost exclusively adenocarcinomas, often categorized as gastric cardia cancers. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common esophageal cancer worldwide:** Squamous Cell Carcinoma. * **Most common esophageal cancer in the West/USA:** Adenocarcinoma (due to rising obesity and GERD). * **Risk Factors for SCC:** Smoking, Alcohol, Achalasia cardia, Tylosis, and Caustic injury. * **Morphology:** SCC often presents as a fungating (exophytic) mass or a circumferential infiltrative lesion leading to "bird-beak" appearance on barium swallow [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 766-767.

Question 363: What is the commonest variety of carcinoma of the stomach?

A. Squamous cell carcinoma
B. Adenocarcinoma (Correct Answer)
C. Colloid carcinoma
D. None of the above

Explanation: **Explanation:** **Adenocarcinoma** is the most common histological type of gastric cancer [1][3], accounting for more than **90-95%** of all malignant tumors of the stomach. The stomach is lined by glandular epithelium (mucosa), and malignancies arising from these cells are classified as adenocarcinomas. According to the **Lauren classification**, these are further divided into two main types: **Intestinal** (associated with chronic gastritis and H. pylori) [1][3] and **Diffuse** (associated with loss of E-cadherin/CDH1 mutation and signet ring cells) [1]. **Analysis of Incorrect Options:** * **Squamous cell carcinoma (SCC):** This is extremely rare in the stomach. SCC typically occurs in the esophagus or the anal canal. When found in the stomach, it is usually an extension from the lower esophagus or arises from squamous metaplasia. * **Colloid (Mucinous) carcinoma:** This is a histological subtype of adenocarcinoma characterized by large extracellular pools of mucin [1]. While it occurs in the stomach, it is far less common than the standard tubular or papillary adenocarcinomas. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Historically the **Antrum** (approx. 50-60%) [1], though the incidence of cardia tumors is rising. * **Risk Factors:** *H. pylori* infection (most important), smoking, high salt intake, and N-nitroso compounds [2]. * **Virchow’s Node:** Left supraclavicular lymph node involvement (Troisier sign). * **Sister Mary Joseph Nodule:** Metastasis to the umbilicus. * **Krukenberg Tumor:** Bilateral ovarian metastasis (characteristically showing signet ring cells). * **Early Gastric Cancer:** Defined as carcinoma limited to the mucosa or submucosa, regardless of lymph node status [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 779. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 779-780. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 354-355.

Question 364: A 54-year-old woman presents with complaints of abdominal fullness and early satiety. She denies a change in bowel habits and states that constipation is her normal state. A radiographic bowel series shows an 'apple core' lesion in her sigmoid colon. Which of the following markers is expected to be elevated in this patient?

A. Alpha-fetoprotein (AFP)
B. Carcinoembryonic antigen (CEA) (Correct Answer)
C. Human chorionic gonadotropin (hCG)
D. Lactate dehydrogenase (LDH)

Explanation: ### Explanation **Correct Answer: B. Carcinoembryonic antigen (CEA)** **Underlying Concept:** The clinical presentation of abdominal fullness, early satiety, and a radiographic **'apple core' lesion** in the sigmoid colon is a classic description of **Colorectal Carcinoma (CRC)**. An 'apple core' lesion represents a circumferential, constricting mass that narrows the bowel lumen, typically seen in the left-sided colon [2]. **Carcinoembryonic antigen (CEA)** is a glycoprotein involved in cell adhesion that is overexpressed in approximately 90% of colorectal cancers. While not used for primary screening due to low specificity, it is the gold-standard marker for **monitoring treatment response** and detecting **tumor recurrence** post-surgery [1]. **Analysis of Incorrect Options:** * **A. Alpha-fetoprotein (AFP):** This is a marker for Hepatocellular Carcinoma (HCC) and non-seminomatous germ cell tumors (e.g., Yolk sac tumor). * **C. Human chorionic gonadotropin (hCG):** This is elevated in pregnancy, Choriocarcinoma, and certain germ cell tumors (e.g., Dysgerminoma or Seminoma). * **D. Lactate dehydrogenase (LDH):** A non-specific marker of cell turnover; it is high-yield for monitoring Dysgerminomas, Lymphomas, and Ewing sarcoma, but lacks specificity for CRC. **NEET-PG High-Yield Pearls:** * **Left-sided CRC:** Presents with "apple core" lesions, altered bowel habits, or intestinal obstruction (as seen here) [2]. * **Right-sided CRC:** Presents with iron deficiency anemia (occult bleeding) and exophytic masses; obstruction is rare due to the larger caliber of the cecum. * **CEA Utility:** Remember, CEA levels do not correlate with the stage of the tumor but are excellent for detecting **recurrence** [1]. * **Most common site of metastasis:** Liver (via the portal circulation) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 821-822. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 207-208.

Question 365: Toxic megacolon is seen as a complication in which of the following conditions?

A. Crohn's disease
B. Ulcerative colitis (Correct Answer)
C. Colonic diverticulosis
D. Miliary TB

Explanation: **Explanation:** **Toxic Megacolon** is a life-threatening complication characterized by total or segmental non-obstructive colonic dilatation (typically >6 cm) associated with systemic toxicity. **1. Why Ulcerative Colitis (UC) is correct:** While toxic megacolon can occur in any inflammatory process of the colon, it is most classically associated with **Ulcerative Colitis**. The underlying mechanism involves severe transmural inflammation (which is unusual for UC but occurs in fulminant cases). This inflammation leads to the release of inflammatory mediators and nitric oxide, which inhibit smooth muscle tone and damage the **myenteric plexus**, resulting in colonic paralysis, thinning of the wall, and rapid dilatation. In severe cases of UC, there is extension of inflammation into the main muscle coats and perforation may occur [1]. **2. Why other options are incorrect:** * **Crohn’s Disease:** Although it can cause toxic megacolon, it is much less common than in UC because the transmural fibrosis characteristic of Crohn’s often prevents the bowel from dilating significantly. * **Colonic Diverticulosis:** This is a structural abnormality (outpouchings). While it can lead to diverticulitis or perforation, it does not typically cause the acute toxic paralytic dilatation seen in megacolon. * **Miliary TB:** This involves hematogenous spread of tuberculosis. While intestinal TB exists (usually ileocecal), it typically presents with strictures or ulceration rather than acute toxic dilatation. **NEET-PG High-Yield Pearls:** * **Radiological Hallmark:** A plain X-ray abdomen showing a colonic diameter **>6 cm** (usually the transverse colon). * **Clinical Sign:** Sudden disappearance of bowel sounds and **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 367-368.

Question 366: Which of the following is NOT considered a high-grade salivary gland malignancy?

A. Basal cell adenocarcinoma (Correct Answer)
B. Mucoepidermoid carcinoma
C. Adenoid cystic carcinoma
D. Salivary duct carcinoma

Explanation: **Explanation:** The grading of salivary gland malignancies is a high-yield topic for NEET-PG, as it determines both prognosis and surgical management. **1. Why Basal Cell Adenocarcinoma is the Correct Answer:** Basal cell adenocarcinoma is considered a **low-grade** malignancy. While it is the malignant counterpart of basal cell adenoma, it is characterized by an indolent clinical course, slow growth, and a low rate of distant metastasis (approx. 10%). It is locally invasive but lacks the aggressive features seen in high-grade tumors. **2. Analysis of Incorrect Options (High-Grade Malignancies):** * **Salivary Duct Carcinoma:** This is one of the most aggressive salivary gland cancers. It histologically resembles high-grade mammary ductal carcinoma and carries a very poor prognosis. * **Adenoid Cystic Carcinoma:** While slow-growing, it is classified as high-grade due to its relentless nature, high rate of **perineural invasion**, and frequent late distant metastases (often to the lungs). [1] * **Mucoepidermoid Carcinoma:** This tumor can be low, intermediate, or high-grade. [1] However, in the context of this question, it is a classic example of a tumor that frequently presents in a high-grade form (especially when the epidermoid component predominates). **3. NEET-PG High-Yield Pearls:** * **Most common salivary gland tumor:** Pleomorphic Adenoma (Benign). * **Most common salivary gland malignancy:** Mucoepidermoid Carcinoma. * **Tumor with highest propensity for perineural invasion:** Adenoid Cystic Carcinoma (Cribriform "Swiss-cheese" pattern). [1] * **Hot Spot:** Warthin’s Tumor (Adenolymphoma) is associated with smoking and is typically "hot" on Technetium-99m pertechnetate scans. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 753-755.

Question 367: Helicobacter pylori infection is associated with which type of gastritis?

A. Type A Gastritis
B. Type B Gastritis (Correct Answer)
C. Autoimmune Gastritis
D. Allergic Gastritis

Explanation: **Explanation:** Chronic gastritis is traditionally classified into two main types based on the etiology and anatomical location: **Type A (Autoimmune)** and **Type B (Bacterial/H. pylori).** [1] **Why Type B is Correct:** Type B gastritis is the most common form of chronic gastritis and is caused by **Helicobacter pylori** infection [1]. It primarily affects the **Antrum** of the stomach (B for **B**acterial and **B**ottom/Antrum) [1]. The bacteria reside in the mucus layer and induce a chronic inflammatory response, which can eventually progress to pangastritis, peptic ulcer disease, and gastric adenocarcinoma or MALToma [1], [2]. **Analysis of Incorrect Options:** * **Type A Gastritis:** This is **Autoimmune** gastritis (A for **A**utoimmune and **A**cid-producing Body/Fundus). It involves antibodies against parietal cells and intrinsic factor, leading to Vitamin B12 deficiency (Pernicious Anemia) and achlorhydria [1]. * **Autoimmune Gastritis:** As mentioned above, this is synonymous with Type A and is not caused by H. pylori [1]. * **Allergic Gastritis:** Also known as Eosinophilic gastritis, this is a rare condition associated with peripheral eosinophilia and elevated IgE, usually triggered by food allergens, not bacterial infection. **NEET-PG High-Yield Pearls:** * **Location:** Type A = Body/Fundus; Type B = Antrum [1]. * **H. pylori Gold Standard Diagnosis:** Endoscopic biopsy followed by **Rapid Urease Test (RUT)** or Histopathology (Warthin-Starry stain) [1]. * **Non-invasive Test of Choice:** Urea Breath Test (for active infection/follow-up). * **Complications:** H. pylori is a Group 1 Carcinogen; it is the most common cause of **MALToma** (which can regress with H. pylori eradication) [1], [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 770-772. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 356-357.

Question 368: What is the most common extranodal site for non-Hodgkin's lymphoma?

A. Stomach (Correct Answer)
B. Brain
C. Intestines
D. Tonsils

Explanation: **Explanation:** The correct answer is **Stomach (Option A)**. While lymphomas primarily arise in the lymph nodes, approximately 25-40% of Non-Hodgkin Lymphomas (NHL) occur at extranodal sites. The **Gastrointestinal (GI) tract** is the most common extranodal location, and within the GI tract, the **stomach** is the most frequent site (accounting for 50-60% of gastric lymphomas), followed by the small intestine and ileocecal region [1]. Most gastric lymphomas are either MALTomas (Mucosa-Associated Lymphoid Tissue) or Diffuse Large B-Cell Lymphomas (DLBCL) [1]. **Analysis of Incorrect Options:** * **Brain (Option B):** Primary Central Nervous System (CNS) lymphoma is rare in the general population, though its incidence is higher in immunocompromised patients (e.g., HIV/AIDS). * **Intestines (Option C):** While the small intestine is the second most common site in the GI tract, it is significantly less common than the stomach. Small bowel lymphomas are often associated with Celiac disease (EATL). * **Tonsils (Option D):** The Waldeyer’s ring (including tonsils) is a common site in the head and neck region, but it ranks below the GI tract in overall frequency. **High-Yield Clinical Pearls for NEET-PG:** * **H. pylori Association:** There is a strong causal link between *Helicobacter pylori* infection and Gastric MALToma [1]. Eradication of the bacteria can lead to tumor regression in early stages. * **Cytogenetics:** Gastric MALToma is frequently associated with the **t(11;18)(q21;q21)** translocation. * **Most Common Histology:** Overall, the most common histological subtype of extranodal NHL is **Diffuse Large B-Cell Lymphoma (DLBCL)** [1]. * **IPSID:** Immunoproliferative Small Intestinal Disease (a variant of MALT lymphoma) is specifically associated with the proximal small intestine and alpha-heavy chain disease. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 356-357.

Question 369: A Mallory-Weiss tear occurs at which anatomical location?

A. Gastro-oesophageal junction (Correct Answer)
B. Duodeno-jejunal flexure
C. Ileo-caecal junction
D. Colo-rectal junction

Explanation: **Explanation:** **Mallory-Weiss Syndrome** refers to longitudinal mucosal lacerations at the **gastro-oesophageal (GE) junction** or the proximal gastric mucosa. These tears are classically caused by a sudden, sharp increase in intra-abdominal pressure, typically due to forceful retching or vomiting (often associated with acute alcohol intoxication or eating disorders). * **Why Option A is correct:** The GE junction is the point of maximum mechanical stress during the retrograde propulsion of gastric contents against a closed or poorly coordinated sphincter. The sudden distension causes the mucosa to tear, leading to hematemesis (vomiting of blood). * **Why Options B, C, and D are incorrect:** These junctions (Duodeno-jejunal, Ileo-caecal, and Colo-rectal) are not physiological sites of high-pressure stress during vomiting. They are involved in different pathologies, such as the Ligament of Treitz (B), Crohn’s disease or intussusception (C), and malignancy or hemorrhoids (D). **High-Yield Clinical Pearls for NEET-PG:** 1. **Clinical Presentation:** Typically presents as **painful hematemesis** following an episode of non-bloody vomiting (distinguish from Boerhaave Syndrome, which involves transmural rupture and excruciating retrosternal pain). 2. **Risk Factors:** Chronic alcoholism (most common) and Hiatal hernia (present in ~75% of cases as it increases the pressure gradient). 3. **Diagnosis:** Upper GI Endoscopy is the gold standard, showing linear mucosal tears crossing the GE junction. 4. **Prognosis:** Most tears are superficial and heal spontaneously without surgical intervention.

Question 370: A 68-year-old man has had "heartburn" and substernal pain after meals for 25 years. For the past year, he has had increased pain with difficulty swallowing both liquids and solids. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows an ulcerated lower esophageal mass that nearly occludes the lumen of the esophagus. A biopsy specimen of this mass is most likely to show which of the following neoplasms?

A. Adenocarcinoma (Correct Answer)
B. Carcinoid tumor
C. Leiomyosarcoma
D. Non-Hodgkin lymphoma

Explanation: ### **Explanation** **1. Why Adenocarcinoma is Correct:** The patient presents with a long-standing history (25 years) of "heartburn" and substernal pain, which are classic symptoms of **Gastroesophageal Reflux Disease (GERD)**. Chronic GERD leads to **Barrett’s Esophagus**, a metaplastic change where stratified squamous epithelium is replaced by intestinal-type columnar epithelium (with goblet cells) [3]. This metaplasia is the primary precursor for **Esophageal Adenocarcinoma** [1]. The recent development of dysphagia (difficulty swallowing) and an ulcerated mass in the **lower third** of the esophagus are hallmark clinical presentations of this malignancy [1]. **2. Why the Other Options are Incorrect:** * **Carcinoid Tumor:** These are neuroendocrine tumors that rarely occur in the esophagus. They typically present as small, firm submucosal nodules rather than large, ulcerated occlusive masses. * **Leiomyosarcoma:** This is a rare malignant smooth muscle tumor. While it can cause dysphagia, it usually presents as a large intramural mass rather than an ulcerated mucosal lesion associated with chronic GERD. * **Non-Hodgkin Lymphoma:** Primary esophageal lymphoma is extremely rare. It typically occurs in immunocompromised patients and does not have a strong association with long-term reflux symptoms. **3. NEET-PG High-Yield Pearls:** * **Location:** Adenocarcinoma typically involves the **lower 1/3rd** (distal) esophagus, whereas Squamous Cell Carcinoma (SCC) most commonly involves the **middle 1/3rd** [1], [2]. * **Risk Factors:** For Adenocarcinoma, the main risk factors are GERD, Obesity, and Barrett’s Esophagus [3]. For SCC, the main risk factors are Smoking and Alcohol. * **Sequence:** Chronic GERD → Barrett’s Esophagus (Metaplasia) → Dysplasia → Adenocarcinoma [1]. * **Biopsy Finding:** Look for mucin-producing glandular structures on histology [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 764-766. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 766-767. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 348-349.

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