Gastrointestinal Pathology Practice Questions

Q: Where does ulcerative colitis typically begin?

Rectum. **Explanation:** Ulcerative Colitis (UC) is a chronic inflammatory bowel disease characterized by continuous mucosal inflammation. The hallmark of UC is its predictable anatomical progression: it **always involves the rectum** (proctitis) and extends proximally in a continuous, symmetrical fashion without "skip lesions" [1]. * **Why Rectum is Correct:** In virtually 100% of cases, the disease originates in the rectum [1]. From there, it may remain localized or spread proximally to involve the sigmoid, descending, or the entire colon (pancolitis). * **Why other options are incorrect:** * **Transverse and Descending Colon:** While these areas are frequently involved, they are affected as a result of proximal spread from the rectum, rather than being the primary site of origin. * **Caecum:** This is the most proximal part of the large intestine. While it is involved in pancolitis, it is not the starting point. (Note: A "caecal patch" can sometimes be seen in distal UC, but the rectum remains the primary site). **High-Yield NEET-PG Pearls:** 1. **Continuity:** Unlike Crohn’s disease (which is patchy/transmural), UC is **continuous** and limited to the **mucosa and submucosa** [1]. 2. **Backwash Ileitis:** In severe pancolitis, the terminal ileum may show superficial inflammation; this is the only time UC "crosses" the ileocecal valve [1]. 3. **Microscopy:** Look for **Crypt Abscesses** (neutrophils in crypt lumens) and crypt distortion. 4. **Clinical Sign:** Lead-pipe appearance on barium enema due to loss of haustrations. 5. **Risk:** UC carries a higher risk of **Toxic Megacolon** and **Adenocarcinoma** compared to Crohn’s. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 367-368.

Q: What is the most common site of MALToma?

Stomach. **Explanation:** **MALToma (Mucosa-Associated Lymphoid Tissue lymphoma)** is a type of extranodal marginal zone B-cell lymphoma. Under normal physiological conditions, the stomach lacks organized lymphoid tissue. However, chronic inflammation—most commonly due to **_Helicobacter pylori_ infection**—induces the formation of acquired MALT in the gastric mucosa [1]. Chronic antigenic stimulation leads to the proliferation of B-cells, eventually resulting in neoplastic transformation. * **Stomach (Correct):** It is the **most common site** for extranodal lymphomas, accounting for approximately 50% of all cases. Within the GI tract, the stomach is the site of origin for about 85% of MALTomas [1]. * **Neck & Mediastinum (Incorrect):** While nodal lymphomas (like Hodgkin or Diffuse Large B-cell Lymphoma) frequently involve cervical or mediastinal lymph nodes, MALToma is specifically an **extranodal** entity. * **Vertebra (Incorrect):** Bone involvement is characteristic of Multiple Myeloma or metastatic disease, not MALToma. **High-Yield Clinical Pearls for NEET-PG:** * **Association:** Strongly linked to **_H. pylori_** (80% of cases) [1]. Eradication of the bacteria with antibiotics can lead to complete regression of the tumor in early stages. * **Cytogenetics:** The most common translocation is **t(11;18)(q21;q21)**, involving the *API2-MLT* gene fusion. This translocation is typically associated with resistance to _H. pylori_ eradication therapy. * **Histology:** Characterized by **lymphoepithelial lesions** (invasion of gastric glands by neoplastic B-cells). * **Markers:** CD19+, CD20+, CD22+, and **CD5- / CD10-** (helps differentiate from Mantle cell and Follicular lymphoma). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 356-357.

Q: What type of polyps are characteristic of Peutz-Jeghers syndrome?

Hamartomatous. **Explanation:** **Peutz-Jeghers Syndrome (PJS)** is an autosomal dominant disorder characterized by the development of multiple **Hamartomatous polyps** throughout the gastrointestinal tract, most commonly in the small intestine [1]. These polyps are non-neoplastic malformations consisting of disorganized native tissue. Histologically, they show a characteristic "Christmas tree" branching pattern of smooth muscle (arising from the muscularis mucosae) covered by normal-appearing intestinal epithelium [1]. **Analysis of Options:** * **Option B (Correct):** Hamartomatous polyps are the hallmark of PJS [1]. They are caused by a germline mutation in the **STK11 (LKB1)** tumor suppressor gene on chromosome 19p13 [1]. * **Option A (Incorrect):** Villous adenomas are neoplastic epithelial polyps with a high risk of malignant transformation, typically associated with the sporadic adenoma-carcinoma sequence or Familial Adenomatous Polyposis (FAP). * **Option C (Incorrect):** Hyperplastic polyps are the most common non-neoplastic polyps in the colon, resulting from decreased epithelial cell turnover. They are not the defining feature of PJS. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Mucocutaneous hyperpigmentation (melanotic macules on lips, buccal mucosa, and digits) + Gastrointestinal hamartomatous polyps + Increased risk of visceral cancers [1]. * **Cancer Risk:** Patients have a significantly increased risk of colorectal, pancreatic, breast, lung, ovarian (Sertoli cell tumors), and uterine cancers [1]. * **Common Complication:** Intussusception is a frequent surgical emergency in these patients as the large polyps act as lead points. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 813-814.

Q: Which of the following autosomal dominant disorders is characterized by the formation of multiple gastrointestinal polyps along with pigmented lesions around the oral cavity?

Peutz-Jeghers syndrome. **Explanation:** **Peutz-Jeghers Syndrome (PJS)** is the correct answer. It is an autosomal dominant condition caused by a germline mutation in the **STK11 (LKB1)** gene on chromosome 19 [1]. It is classically defined by the triad of: 1. **Hamartomatous polyps:** Multiple, characteristic "arborizing" polyps most commonly found in the small intestine [1]. 2. **Mucocutaneous hyperpigmentation:** Dark blue-to-brown macules (melanocytic spots) located around the mouth, lips, buccal mucosa, palms, and soles [1]. 3. **Increased Cancer Risk:** Significant risk for both GI (colorectal, pancreatic) and extra-GI malignancies (breast, ovary, testis) [1]. **Why the other options are incorrect:** * **Rotor Syndrome:** A benign autosomal recessive condition causing conjugated hyperbilirubinemia due to impaired hepatic storage of bilirubin. It does not involve polyps or pigmentation. * **Gardner Syndrome:** A variant of Familial Adenomatous Polyposis (FAP). While it features GI polyps (adenomatous, not hamartomatous), it is characterized by extra-intestinal manifestations like osteomas, epidermal cysts, and desmoid tumors, rather than perioral pigmentation. * **Cowden Disease:** Part of the PTEN hamartoma tumor syndrome [1]. It features GI hamartomas but is distinguished by macrocephaly, trichilemmomas (skin tumors), and a high risk of thyroid and endometrial cancer [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** PJS polyps show a "Christmas tree" appearance due to branching frameworks of smooth muscle (arborization). * **Intussusception:** The most common surgical complication of PJS polyps in young patients. * **STK11:** Remember this gene; it is a tumor suppressor that regulates cell polarity and metabolism [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 813-814.

Question 1

Which of the following is NOT a predisposing cause for carcinoma of the stomach?

Accepted Answer

Hyperplastic polyp

Answer

Chronic gastric atrophy

Answer

Intestinal metaplasia grade III

Answer

Pernicious anemia

Question 2

Which of the following is NOT true about solitary rectal ulcer syndrome?

Accepted Answer

Lamina propria infiltration with lymphocytes

Answer

Increased muscle layer proliferation

Answer

Crypt distortion

Answer

Subepithelial fibrosis

Question 3

A 63-year-old man undergoes a screening colonoscopy and is found to have a polyp in his sigmoid colon. Which type of polyp is most associated with malignancy?

Accepted Answer

Villous adenoma

Answer

Tubular adenoma

Answer

Tubulovillous adenoma

Answer

1 cm polyp

Question 4

Where does ulcerative colitis typically begin?

Accepted Answer

Rectum

Answer

Transverse colon

Answer

Caecum

Answer

Descending colon

Question 5

Zollinger-Ellison syndrome is not caused by tumors from which of the following organs?

Accepted Answer

Colon

Answer

Pancreas

Answer

Ovary

Answer

Duodenum

Question 6

What is the most common site of MALToma?

Accepted Answer

Stomach

Answer

Neck

Answer

Mediastinum

Answer

Vertebra

Question 7

What type of polyps are characteristic of Peutz-Jeghers syndrome?

Accepted Answer

Hamartomatous

Answer

Villous

Answer

Hyperplastic

Answer

None of the above

Question 8

What is the most common type of carcinoma of the right colon?

Accepted Answer

Ulcerative

Answer

Stenosing

Answer

Tubular

Answer

Fungating

Question 9

Which inflammatory bowel disease is characterized by transmural involvement and skip lesions?

Accepted Answer

Crohn's disease

Answer

Ulcerative colitis

Answer

Shigella infection

Answer

Clostridium infection

Question 10

Which of the following autosomal dominant disorders is characterized by the formation of multiple gastrointestinal polyps along with pigmented lesions around the oral cavity?

Accepted Answer

Peutz-Jeghers syndrome

Answer

Rotor syndrome

Answer

Gardner syndrome

Answer

Cowden disease

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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