Gastrointestinal Pathology Practice Questions

Q: In Peutz-Jeghers syndrome, where are polyps characteristically seen?

Small bowel. **Explanation:** Peutz-Jeghers Syndrome (PJS) is an autosomal dominant condition characterized by the association of gastrointestinal hamartomatous polyps and mucocutaneous hyperpigmentation [1]. **1. Why Small Bowel is Correct:** The hallmark of PJS is the presence of **hamartomatous polyps**, which are most commonly found in the **small intestine** (specifically the jejunum) [1]. These polyps are histologically distinct, featuring a characteristic "Christmas tree" branching pattern of smooth muscle (arborization) surrounding the glandular epithelium [1]. While they can occur anywhere in the GI tract, the small bowel is the most frequent site (approx. 60-90% of cases), often leading to complications like intussusception. **2. Why Other Options are Incorrect:** * **Anus & Rectum:** While polyps can occur in the colon and rectum (about 25-30% of cases), they are significantly less common than in the small bowel [1]. PJS is distinct from Familial Adenomatous Polyposis (FAP), where the rectum is almost always involved. * **Stomach:** Gastric involvement occurs in about 25% of patients, making it a secondary site compared to the primary involvement of the small intestine [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Mutation in the **STK11 (LKB1)** gene on chromosome 19p13 [1]. * **Clinical Triad:** Hamartomatous polyps + Mucocutaneous pigmentation (melanotic macules on lips, buccal mucosa, and digits) + Increased cancer risk [1]. * **Cancer Risk:** Patients have a significantly increased risk of both GI (colorectal, pancreatic) and extra-GI malignancies (breast, ovary, uterus, and **Sertoli cell tumors** of the testis) [1]. * **Complication:** The most common surgical complication is **intussusception** due to the polyp acting as a lead point. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 813.

Q: Periodic Acid Schiff (PAS)-Positive macrophages deposited in the lamina propria of the gastrointestinal tract, in a patient with a history of abdominal pain and diarrhea, most likely indicates which diagnosis?

Whipple's disease. **Explanation:** The presence of **PAS-positive, diastase-resistant macrophages** in the lamina propria is the classic histological hallmark of **Whipple’s Disease**. This systemic infection is caused by the gram-positive bacterium *Tropheryma whipplei* [1]. The macrophages accumulate because they are unable to fully digest the bacterial cell walls, which contain glycoproteins that stain brightly with Periodic Acid-Schiff (PAS). **Why the other options are incorrect:** * **Giardiasis:** Characterized by pear-shaped, flagellated trophozoites (resembling "falling leaves" or "owl's eyes") attached to the mucosal surface, not macrophage infiltration. * **Crohn’s Disease:** Features transmural inflammation and **non-caseating granulomas**. While macrophages are present, they do not show the characteristic PAS-positive inclusions seen in Whipple’s. * **Amoebiasis:** Presents with "flask-shaped" ulcers and trophozoites containing ingested red blood cells (erythrophagocytosis). **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Tetrad:** Diarrhea/Malabsorption, Weight loss, Arthralgia (most common early symptom), and Lymphadenopathy [1]. * **Microscopy:** Electron microscopy reveals **"bacilliform bodies"** (the actual bacteria) within the macrophages. * **Differential Diagnosis:** *Mycobacterium avium-intracellulare* (MAI) also shows PAS-positive macrophages but is distinguished by being **Acid-Fast Bacillus (AFB) positive**, whereas *T. whipplei* is AFB negative [1]. * **Treatment:** Long-term antibiotics (usually Ceftriaxone followed by Trimethoprim-sulfamethoxazole). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 798-799.

Question 1

Intestinal villi are swollen and distended. There is accumulation of large granular macrophages, containing material which stains strongly with periodic acid Schiff, in the lamina propria. What is the most probable condition?

Accepted Answer

Whipple's disease

Answer

Secondary steatorrhea

Answer

Sprue

Answer

Coeliac disease

Question 2

The pathological appearance in pseudomembranous colitis consists of?

Accepted Answer

Small ulceration with slough

Answer

Necrosis and gangrene

Answer

Serositis covered by membrane

Answer

Excessive ulceration in serosa

Question 3

In Peutz-Jeghers syndrome, where are polyps characteristically seen?

Accepted Answer

Small bowel

Answer

Anus

Answer

Rectum

Answer

Stomach

Question 4

Which of the following are predisposing factors for gastric carcinoma?

Accepted Answer

All of the above

Answer

Atrophic gastritis

Answer

Hyperplastic polyp

Answer

Adenomatous polyp

Question 5

Periodic Acid Schiff (PAS)-Positive macrophages deposited in the lamina propria of the gastrointestinal tract, in a patient with a history of abdominal pain and diarrhea, most likely indicates which diagnosis?

Accepted Answer

Whipple's disease

Answer

Giardiasis

Answer

Crohn's disease

Answer

Amoebiasis

Question 6

A small intestinal biopsy is diagnostic in which of the following conditions?

Accepted Answer

Whipple's disease

Answer

Abetalipoproteinemia

Answer

Celiac disease

Answer

Agammaglobulinemia

Question 7

All of the following can cause pancreatitis except?

Accepted Answer

Islet cell hyperplasia

Answer

Hyperlipidemia

Answer

Abdominal trauma

Answer

Genetic defect in trypsinogen

Question 8

Which of the following statements about Gastrointestinal Stromal Tumors (GIST) is false?

Accepted Answer

Least common mesenchymal neoplasm of the gastrointestinal tract

Answer

Associated with c-kit mutation

Answer

Most common site is the stomach

Answer

Associated with CD 117

Question 9

Metastatic calcification of the gastrointestinal tract commonly affects the mucosa of:

Accepted Answer

Stomach

Answer

Esophagus

Answer

Ileum

Answer

Rectum

Question 10

Giardia trophozoites in endoscopic study and biopsy of the duodenum are seen in which of the following conditions?

Accepted Answer

Immunoglobulin deficiency

Answer

Lactase deficiency

Answer

Whipple's disease

Answer

Abetalipoproteinemia

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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