Gastrointestinal Pathology Practice Questions

Q: A 45-year-old businesswoman arrives with vague abdominal complaints and has noticed melenic stool. A sigmoidoscopy reveals a 4-cm mass in the upper colon. Which tumor marker should be ordered?

Carcinoembryonic antigen (CEA). **Explanation:** The clinical presentation of a 45-year-old with vague abdominal symptoms, melena (indicating gastrointestinal bleeding), and a 4-cm colonic mass is highly suggestive of **Colorectal Carcinoma (CRC)**. **Why Carcinoembryonic Antigen (CEA) is correct:** CEA is an oncofetal glycoprotein normally produced during fetal development and found in very low levels in adults. It is the most widely used tumor marker for **adenocarcinomas of the colon**. While it lacks the sensitivity and specificity required for primary screening, it is the gold standard for **monitoring treatment response** and detecting **post-operative recurrence** in CRC patients. **Analysis of Incorrect Options:** * **A. $\alpha$-Fetoprotein (AFP):** This is the primary marker for **Hepatocellular Carcinoma (HCC)** and non-seminomatous germ cell tumors (e.g., Yolk sac tumors). * **B. Anti-tumor antibody:** While the immune system may produce antibodies against tumor antigens, these are not standardized or clinically used as diagnostic markers for colon cancer. * **C. Antitumor light chains:** This likely refers to Bence-Jones proteins (monoclonal free light chains), which are diagnostic markers for **Multiple Myeloma**, not solid gastrointestinal tumors. **NEET-PG High-Yield Pearls:** * **CEA** is also elevated in pancreatic, gastric, and breast cancers, as well as in smokers and patients with inflammatory bowel disease (IBD). * **CA 19-9:** Marker for Pancreatic and Cholangiocarcinoma. * **CA-125:** Marker for Ovarian cancer. * **PSA:** Marker for Prostate cancer. * **Rule of Thumb:** Tumor markers are generally used for **prognosis and monitoring**, not for definitive diagnosis (which requires biopsy).

Q: What is the diagnosis?

Linitis plastica. ***Linitis plastica*** - Shows characteristic **"leather bottle" stomach** appearance with diffuse **wall thickening** and **rigid, non-distensible** gastric contour. - Results from **signet-ring cell adenocarcinoma** infiltrating the gastric wall, causing **loss of normal rugal folds** and contracture. *Atrophic gastritis* - Presents with **thin gastric walls** and **loss of rugal folds** due to mucosal atrophy, not wall thickening. - Associated with **parietal cell loss** and **decreased acid production**, often showing a flattened, smooth gastric surface. *Gastric ulcer* - Appears as a **discrete crater-like lesion** with raised edges, not diffuse wall involvement. - Shows **localized mucosal defect** extending into the submucosa, maintaining normal wall thickness elsewhere. *Ménétrier's disease* - Characterized by **enlarged, thickened rugal folds** creating a "cerebriform" pattern, opposite of the smooth appearance seen here. - Results from **foveolar hyperplasia** with **protein-losing gastropathy**, not wall contraction or rigidity.

Q: A 45-year-old HIV-positive male presented with dysphagia. Endoscopy and biopsy were performed. What is the most likely diagnosis based on the endoscopic and histological findings?

Cytomegalovirus (CMV) esophagitis. ***Cytomegalovirus (CMV) esophagitis*** - Characterized by **large linear ulcerations** on endoscopy, typically seen in severely immunocompromised HIV patients with **CD4+ count <50 cells/μL**. - Histologically shows pathognomonic **owl-eye nuclear inclusions** (large eosinophilic intranuclear inclusions with surrounding halo) in infected cells. *Herpes esophagitis* - Endoscopically presents with **small, punched-out ulcers** rather than large linear ulcerations seen in CMV. - Histologically shows **multinucleated giant cells** with **Cowdry A inclusions**, not the characteristic owl-eye inclusions of CMV. *Candida esophagitis* - Endoscopically appears as **white plaques** or **pseudomembranes** that can be wiped off, revealing erythematous mucosa underneath. - Histologically shows **pseudohyphae and budding yeasts** on PAS or GMS staining, without the viral inclusions described. *Pseudomonas esophagitis* - Extremely rare cause of esophagitis, typically occurring only in **severely neutropenic patients** or those with extensive burns. - Would show **gram-negative rod bacteria** on histology and **necrotizing inflammation**, not the viral cytopathic effects described.

Question 1

What is the pathogenesis of a periapical cyst?

Accepted Answer

Proliferation of epithelium

Answer

Increased pressure within the cyst

Answer

Immune-mediated bone destruction

Answer

None of the above

Question 2

Low dietary fiber intake is related to which carcinoma?

Accepted Answer

Colon

Answer

Breast

Answer

Lung

Answer

Kidney

Question 3

Which of the following is FALSE regarding autoimmune atrophic gastritis?

Accepted Answer

Hyperchlorhydria

Answer

Loss of parietal cells

Answer

Hyperplasia of G cells

Answer

Hypertrophy of enterochromaffin cells

Question 4

A 45-year-old businesswoman arrives with vague abdominal complaints and has noticed melenic stool. A sigmoidoscopy reveals a 4-cm mass in the upper colon. Which tumor marker should be ordered?

Accepted Answer

Carcinoembryonic antigen (CEA)

Answer

a-Fetoprotein

Answer

Anti-tumor antibody

Answer

Antitumor light chains

Question 5

Duke's stage C2 refers to carcinoma:

Accepted Answer

Rectum with metastasis to inferior mesenteric lymph nodes

Answer

Bladder penetrating the extravesical fat

Answer

Bladder with metastasis to internal iliac lymph nodes

Answer

With histological features of 75% anaplastic cells

Question 6

What is the diagnosis?

Accepted Answer

Linitis plastica

Answer

Atrophic gastritis

Answer

Gastric ulcer

Answer

Ménétrier's disease

Question 7

What is the diagnosis?

Accepted Answer

Linitis plastica

Answer

Atrophic gastritis

Answer

Gastric ulcer

Answer

Ménétrier's disease

Question 8

Which of the following is NOT considered a premalignant condition?

Accepted Answer

Hyperplastic polyp

Answer

Tubulovillous adenoma

Answer

Familial adenomatosis

Answer

Villous adenoma

Question 9

A peptic ulcer is associated with all of the following conditions except one?

Accepted Answer

Pernicious anemia

Answer

Cirrhosis

Answer

Zollinger-Ellison syndrome

Answer

Primary hyperparathyroidism

Question 10

A 45-year-old HIV-positive male presented with dysphagia. Endoscopy and biopsy were performed. What is the most likely diagnosis based on the endoscopic and histological findings?

Accepted Answer

Cytomegalovirus (CMV) esophagitis

Answer

Herpes esophagitis

Answer

Candida esophagitis

Answer

Pseudomonas esophagitis

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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