Gastrointestinal Pathology Practice Questions

Q: A histopathological image of a cystic lesion is shown. What is the most likely diagnosis?

Papillary cystadenoma lymphomatosum. ***Papillary cystadenoma lymphomatosum*** - Features characteristic **bilayered oncocytic epithelium** lining papillary projections within cystic spaces, creating a distinctive architectural pattern. - Contains **lymphoid stroma with germinal centers**, which is pathognomonic for Warthin's tumor and distinguishes it from other cystic lesions. *Dentigerous cyst* - Shows simple **squamous epithelial lining** derived from dental follicle, lacking the complex papillary architecture. - Associated with **unerupted teeth** and contains dental follicular tissue, not lymphoid stroma. *Odontogenic keratocyst* - Characterized by **parakeratinized stratified squamous epithelium** with a distinctive palisaded basal layer. - Lacks the **papillary projections** and **lymphoid component** seen in papillary cystadenoma lymphomatosum. *Unicystic ameloblastoma* - Features **ameloblastic epithelium** with characteristic **stellate reticulum** and reverse nuclear polarity. - Shows **odontogenic differentiation** patterns, not the oncocytic epithelium and lymphoid stroma of Warthin's tumor.

Q: According to Borrmann's classification, linitis plastica is what type?

Type IV. **Explanation:** Borrmann’s classification is a widely used system for categorizing the macroscopic (gross) appearance of advanced gastric adenocarcinoma. It is a high-yield topic for NEET-PG as it correlates morphology with clinical behavior. **Correct Answer: Type IV (Diffuse Infiltrative)** Type IV refers to the **diffuse infiltrating type**, also known as **Linitis Plastica** ("leather bottle stomach"). In this type, the tumor cells (often signet-ring cells) infiltrate the entire stomach wall, causing marked thickening and rigidity without a distinct mass or ulcer [1]. This results in the loss of gastric rugae and a "shrunken" appearance on imaging. **Analysis of Incorrect Options:** * **Type I (Polypoid):** These are circumscribed, solitary, cauliflower-like masses that protrude into the lumen without significant ulceration. * **Type II (Ulcerated/Circumscribed):** These are well-defined, "saucer-like" ulcers with clearly demarcated, raised margins. They do not show extensive infiltration into the surrounding mucosa [1]. * **Type III (Ulcerated-Infiltrating):** These are ulcers with poorly defined margins where the tumor cells are seen infiltrating into the surrounding gastric wall. **Clinical Pearls for NEET-PG:** * **Linitis Plastica** is most commonly associated with **Lauren’s Diffuse type** gastric cancer and is linked to mutations in the **CDH1 gene** (E-cadherin) [1]. * It has the **worst prognosis** among all Borrmann types due to its aggressive spread and late presentation. * On Barium swallow, it presents as the classic **"Leather Bottle"** appearance due to restricted distensibility [1]. * **Virchow’s node** (left supraclavicular) and **Krukenberg tumor** (bilateral ovarian spread) are common distant involvements. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 779-780.

Q: What is the most common type of salivary gland neoplasm?

Pleomorphic adenoma. **Explanation:** **Pleomorphic Adenoma** (Option B) is the correct answer as it is the most common neoplasm of the salivary glands, accounting for approximately 60% of all tumors in the parotid gland. It is a benign mixed tumor characterized by a combination of epithelial, myoepithelial, and mesenchymal elements (often showing chondroid or myxoid stroma). It typically presents as a slow-growing, painless, mobile mass, most frequently located in the superficial lobe of the parotid gland [1]. **Analysis of Incorrect Options:** * **Adenoid Cystic Carcinoma (Option A):** While it is a common malignant tumor of the minor salivary glands, it is not the most common overall [1]. It is high-yield for its characteristic "Swiss-cheese" microscopic pattern and its tendency for perineural invasion. * **Epidermoid Carcinoma (Option C):** Also known as Squamous Cell Carcinoma, this is rare as a primary salivary gland tumor and usually represents metastasis or extension from overlying skin. * **Adenocarcinoma (Option D):** This is a broad category of malignant tumors. While Mucoepidermoid carcinoma is the most common *malignant* salivary gland tumor [1], "Adenocarcinoma" (NOS) is less frequent than Pleomorphic adenoma. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Parotid gland (80% of all salivary tumors). * **Most common benign tumor:** Pleomorphic Adenoma [1]. * **Most common malignant tumor:** Mucoepidermoid Carcinoma [1]. * **Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum):** Second most common benign tumor; strongly associated with smoking and often bilateral. * **Carcinoma ex pleomorphic adenoma:** Refers to the malignant transformation of a long-standing pleomorphic adenoma, signaled by sudden rapid growth [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 751-753.

Q: All are true about the pathological changes in pseudomembranous enterocolitis, EXCEPT:

Rectal sparing is a feature. **Explanation:** Pseudomembranous enterocolitis (PMC) is an inflammatory condition of the colon, most commonly caused by toxins produced by **_Clostridioides difficile_** following broad-spectrum antibiotic use. **Why Option D is the Correct Answer (The Exception):** In pseudomembranous colitis, the involvement is typically diffuse. Unlike Crohn’s disease, which is characterized by "skip lesions" and frequent rectal sparing, **PMC usually involves the rectum.** In fact, sigmoidoscopy/proctoscopy is a primary diagnostic tool because the characteristic "volcano lesions" and yellowish-white plaques are readily visible in the rectum and sigmoid colon in the vast majority of cases. **Analysis of Incorrect Options:** * **Option A & B:** While the name suggests "enterocolitis," the disease is predominantly **confined to the colonic mucosa**. It typically involves the **entire colon** (pancolitis), although the severity of plaque formation may vary across segments. * **Option C:** The hallmark pathology involves focal surface **epithelial necrosis and erosion**. This is accompanied by an exudate of fibrin, neutrophils, and necrotic debris that erupts from the crypts (the "volcano" or "mushroom" lesion) to form the classic pseudomembrane. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Most common offending antibiotics are **Clindamycin**, Fluoroquinolones, and Cephalosporins. * **Morphology:** The "Volcano Lesion" is the pathognomonic histological feature. * **Diagnosis:** Gold standard is the **Cell Cytotoxicity Assay**; however, GDH antigen and Toxin A/B PCR are more commonly used in clinical practice. * **Treatment:** First-line therapy is oral **Vancomycin** or Fidaxomicin (Metronidazole is now secondary).

Q: Paget's disease of the anal canal is classified as:

Intra-epithelial adenocarcinoma. **Explanation:** **Extramammary Paget’s Disease (EMPD)** of the anal canal is a rare, slow-growing malignancy characterized by the presence of malignant glandular cells within the squamous epithelium of the skin. **1. Why the correct answer is right:** Paget’s disease is histologically defined as an **intra-epithelial adenocarcinoma**. It arises from intraepidermal pluripotent stem cells or as an extension of an underlying visceral malignancy (like rectal or bladder cancer). The characteristic "Paget cells" are large, pale cells containing **mucin**, which stains positive with **PAS, Alcian Blue, and Mucicarmine**. This glandular (adenocarcinoma) nature distinguishes it from squamous cell pathologies. **2. Why the other options are wrong:** * **Option A (Squamous cell carcinoma in situ):** This is also known as **Bowen’s Disease** of the anus. While both present as plaques, Bowen’s involves dysplastic keratinocytes, not mucin-producing glandular cells. * **Option B (Squamous cell adenoma):** This is a non-standard clinical term. Adenomas are by definition glandular, while "squamous" refers to the lining; the two are not typically combined in this manner. * **Option C (Marginal anal cell carcinoma):** This refers to squamous cell carcinomas arising from the anal margin (perianal skin). These are treated like skin cancers, unlike Paget’s, which requires screening for internal malignancies. **Clinical Pearls for NEET-PG:** * **Presentation:** Often misdiagnosed as chronic eczema or pruritus ani; presents as a well-demarcated, erythematous, "velvety" eczematous plaque. * **Associated Malignancy:** Up to 40% of patients have an underlying synchronous visceral cancer (most commonly **colorectal adenocarcinoma**). * **Diagnosis:** Punch biopsy is essential. * **Treatment:** Wide local excision (WLE). If an underlying rectal cancer is present, an Abdominoperineal Resection (APR) may be required.

Question 1

What is the most common site of adenocarcinoma in the small intestine?

Accepted Answer

Duodenum

Answer

Jejunum

Answer

Ileum

Answer

Appendix

Question 2

A histopathological image of a cystic lesion is shown. What is the most likely diagnosis?

Accepted Answer

Papillary cystadenoma lymphomatosum

Answer

Dentigerous cyst

Answer

Odontogenic keratocyst

Answer

Unicystic ameloblastoma

Question 3

According to Borrmann's classification, linitis plastica is what type?

Accepted Answer

Type IV

Answer

Type I

Answer

Type II

Answer

Type III

Question 4

What is Turner hypoplasia?

Accepted Answer

Hypoplasia due to local trauma or infection

Answer

Hypoplasia due to systemic infection

Answer

Hypoplasia due to congenital syphilis

Answer

Hypoplasia due to fluoride ingestion

Question 5

What is the most common type of salivary gland neoplasm?

Accepted Answer

Pleomorphic adenoma

Answer

Adenoid cystic carcinoma

Answer

Epidermoid carcinoma

Answer

Adenocarcinoma

Question 6

A 14-year-old girl with a history of prolonged fever and abdominal discomfort is observed to have splenomegaly and leucopenia. In the course of the disease, she developed an acute abdominal event and died. Which of the following is the likely finding on autopsy?

Accepted Answer

Longitudinal ulcers

Answer

Transverse ulcers

Answer

Pinpoint ulcers

Answer

Pseudopolyps

Question 7

Which gene is mutated in familial gastric cancer?

Accepted Answer

E-cadherin

Answer

APC

Answer

CDKN2A

Answer

PTEN

Question 8

All are true about the pathological changes in pseudomembranous enterocolitis, EXCEPT:

Accepted Answer

Rectal sparing is a feature

Answer

It is confined to the colonic mucosa

Answer

The whole colon is involved

Answer

The epithelium is eroded and necrotic in certain areas

Question 9

Paget's disease of the anal canal is classified as:

Accepted Answer

Intra-epithelial adenocarcinoma

Answer

Squamous cell carcinoma in situ

Answer

Squamous cell adenoma

Answer

Marginal anal cell carcinoma

Question 10

Upper GI endoscopy and biopsy from the lower esophagus in a 48-year-old lady with chronic heartburn shows the presence of columnar epithelium with goblet cells. This feature is most likely consistent with:

Accepted Answer

Metaplasia

Answer

Dysplasia

Answer

Hyperplasia

Answer

Carcinoma in situ

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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