Gastrointestinal Pathology Practice Questions

Q: What is the immuno-marker for GIST?

CD 117. **Explanation:** **Gastrointestinal Stromal Tumor (GIST)** is the most common mesenchymal tumor of the gastrointestinal tract. It originates from the **Interstitial Cells of Cajal (ICC)**, which serve as the electrical pacemakers of the gut. **1. Why CD 117 is correct:** Approximately 95% of GISTs express **CD 117**, which is the protein product of the **c-KIT proto-oncogene** [1]. This gene encodes a receptor tyrosine kinase. Mutations in c-KIT lead to constitutive activation of the kinase, driving uncontrolled cell proliferation [1]. Identifying CD 117 via immunohistochemistry (IHC) is the gold standard for diagnosis and is crucial because it predicts responsiveness to targeted therapy with **Imatinib** (a tyrosine kinase inhibitor) [1]. **2. Why the other options are incorrect:** * **CD 4:** A marker primarily found on T-helper cells, monocytes, and macrophages; it is used in the evaluation of lymphomas and HIV progression. * **CD 100 (Sema4D):** Involved in immune cell signaling and axonal guidance; it has no diagnostic relevance for GIST. * **CD 45:** Also known as **Leukocyte Common Antigen (LCA)**. It is a pan-leukocyte marker used to identify tumors of hematopoietic origin (lymphomas) and differentiate them from carcinomas or sarcomas. **High-Yield Facts for NEET-PG:** * **DOG1 (Discovered on GIST-1):** The most sensitive and specific marker for GIST, especially useful in CD 117-negative cases. * **Genetics:** Most cases involve **c-KIT** mutations; a subset involves **PDGFRA** mutations [1]. * **Morphology:** Most GISTs show a **spindle cell** pattern (70%), followed by epithelioid types. * **Location:** The **stomach** (60%) is the most common site, followed by the small intestine. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 782-784.

Question 1

Cobblestone appearance is seen in which of the following conditions?

Accepted Answer

Crohn's disease

Answer

Ulcerative colitis

Answer

Appendicitis

Answer

Carcinoma rectum

Question 2

E-cadherin mutation is seen in which type of gastric carcinoma classification?

Accepted Answer

Lauren diffuse type

Answer

Borrmann ulcerative type

Answer

Borrmann ulceroproliferative type

Answer

Intestinal type

Question 3

All of the following are true about Barrett's esophagus, EXCEPT:

Accepted Answer

It is associated with esophageal varices.

Answer

It is a consequence of prolonged gastroesophageal reflux disease (GERD).

Answer

It is a premalignant condition.

Answer

The lower esophageal mucosa is replaced by intestinal-type epithelium.

Question 4

A 58-year-old woman undergoes routine colonoscopy. A 2-cm submucosal nodule is identified in the appendix. Biopsy of the nodule shows nests of cells with round, uniform nuclei. Electron microscopy reveals numerous neuroendocrine granules in the cytoplasm. This patient's neoplastic disease is associated with which of the following clinical features?

Accepted Answer

Flushing and wheezing

Answer

Congestive heart failure

Answer

Muscular dystrophy

Answer

Progressive systemic sclerosis

Question 5

What is the immuno-marker for GIST?

Accepted Answer

CD 117

Answer

CD 4

Answer

CD 100

Answer

CD45

Question 6

A salivary gland tumor that histologically shows a double layer of epithelial cells based on a reactive lymphoid stroma is:

Accepted Answer

Warthin tumor

Answer

Pleomorphic adenoma

Answer

Mucoepidermoid carcinoma

Answer

Acinic cell tumor

Question 7

A 71-year-old male presents with dysphagia and is found to have a 5-cm mass that is located in the middle third of the esophagus and extends into adjacent lung tissue. A biopsy from this mass would most likely reveal?

Accepted Answer

Infiltrating sheets of cells forming keratin

Answer

A mass composed of benign cartilage

Answer

A mass composed of benign smooth-muscle cells

Answer

Infiltrating groups of cells forming glandular structures

Question 8

The presence of anti-Saccharomyces cerevisiae antibody is a surrogate marker of which of the following conditions?

Accepted Answer

Crohn's disease

Answer

Celiac disease

Answer

Ulcerative colitis

Answer

Tropical sprue

Question 9

Which of the following is true about celiac disease?

Accepted Answer

All of the above

Answer

Villous atrophy

Answer

Crypt hyperplasia

Answer

Infiltration of lymphocytes

Question 10

Gardner's syndrome is a rare hereditary disorder involving the colon. It is characterized by

Accepted Answer

Polyposis of the colon, osteomas, epidermal inclusion cysts, and fibrous tumors of the skin.

Answer

Polyposis of the colon, thyroid cancer, and skin tumors.

Answer

Polyposis in the jejunum, pituitary adenoma, and skin tumors.

Answer

All of the above.

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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