General Pathology Practice Questions

Q: MIC-2 is a marker of:

Ewing's sarcoma. **Explanation:** **MIC-2 (CD99)** is a cell surface glycoprotein encoded by the *MIC2* gene. It is the most sensitive immunohistochemical marker for the **Ewing’s Sarcoma/Primitive Neuroectodermal Tumor (PNET)** family of tumors. In Ewing’s sarcoma, MIC-2 typically shows a strong, diffuse membranous staining pattern, which is crucial for differentiating it from other "small round blue cell tumors" of childhood. **Analysis of Options:** * **Ewing's Sarcoma (Correct):** Characterized by the chromosomal translocation **t(11;22)(q24;q12)**, leading to the *EWS-FLI1* fusion gene. MIC-2/CD99 is positive in over 95% of cases. * **Osteosarcoma:** The primary markers are **SATB2** and Osteonectin. While some variants may show focal CD99 positivity, it is not a diagnostic marker for Osteosarcoma [1], [2]. * **Dermatofibrosarcoma Protuberans (DFSP):** This is characterized by the marker **CD34** and the translocation t(17;22). * **Alveolar Soft Part Sarcoma:** This tumor is characterized by the **ASPSCR1-TFE3** fusion gene and shows nuclear positivity for **TFE3**. **High-Yield Clinical Pearls for NEET-PG:** * **CD99 (MIC-2)** is highly sensitive but **not specific**; it can also be positive in T-cell Lymphoblastic Lymphoma, Synovial Sarcoma, and Solitary Fibrous Tumors. * **Ewing’s Sarcoma Radiology:** Classically presents with an "onion-skin" periosteal reaction. * **PAS Positivity:** Ewing’s sarcoma cells are often PAS-positive due to the presence of cytoplasmic glycogen (diastase sensitive). * **Homer-Wright Rosettes:** Their presence indicates neuroectodermal differentiation (PNET). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1200.

Q: What is LATS?

IgG. **Explanation:** **LATS (Long-Acting Thyroid Stimulator)** is a clinical term historically used to describe the autoantibodies found in patients with **Graves' Disease**. [1] **Why IgG is the correct answer:** LATS belongs to the **IgG (Immunoglobulin G)** class of antibodies. Specifically, these are **Thyroid Stimulating Immunoglobulins (TSI)**. They act as agonists by binding to the TSH receptors on the thyroid follicular cells. [1] Unlike physiological TSH, which is regulated by negative feedback, LATS provides prolonged stimulation (hence "Long-Acting"), leading to excessive production of T3 and T4 and the characteristic hyperthyroidism of Graves' disease. **Analysis of Incorrect Options:** * **IgM:** While IgM is the first antibody produced in an immune response, it is not the mediator of Graves' disease. LATS is a high-affinity, mature IgG antibody. * **Glycoprotein:** TSH (Thyroid Stimulating Hormone) itself is a glycoprotein, but LATS is an antibody (protein). * **IgA:** IgA is primarily involved in mucosal immunity and is not associated with the pathogenesis of autoimmune thyroiditis. **NEET-PG High-Yield Pearls:** * **Type of Hypersensitivity:** Graves' disease (mediated by LATS/TSI) is a classic example of **Type II Hypersensitivity** (specifically Type IIb or stimulating type). [1] * **Placental Transfer:** Because LATS is an **IgG**, it can cross the placenta. This explains why infants born to mothers with Graves' disease may suffer from **Neonatal Thyrotoxicosis**. * **Triad of Graves:** Hyperthyroidism, Exophthalmos (due to retro-orbital inflammation), and Pretibial Myxedema. * **HLA Association:** Strongly associated with **HLA-DR3** and **HLA-B8**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 213-214.

Q: Gamna Gandy bodies contain hemosiderin and what else?

Ca++. **Explanation:** **Gamna-Gandy bodies** (also known as Siderofibrotic nodules) are small, firm, brownish-yellow nodules found in the spleen. They represent organized areas of focal hemorrhage within the splenic parenchyma. [1] 1. **Why Ca++ is correct:** When focal hemorrhage occurs (commonly due to portal hypertension), the hemoglobin from extravasated red blood cells breaks down into **hemosiderin**. [1] Over time, these areas undergo fibrosis. A key pathological feature is the deposition of inorganic salts—specifically **Calcium (Ca++)**—along with iron onto the fibrous connective tissue and elastic fibers. This process is a form of dystrophic calcification. Under a microscope, they appear as golden-yellow or brown deposits that stain positive with Prussian Blue (for iron) and Von Kossa (for calcium). 2. **Why other options are wrong:** * **Na+ (Sodium) and Cl- (Chloride):** These are the primary extracellular electrolytes involved in fluid balance and action potentials; they do not form solid precipitates or "bodies" within fibrotic tissues. * **Mg++ (Magnesium):** While magnesium can be found in some physiological crystals (like struvite), it is not a constituent of Gamna-Gandy bodies. **Clinical Pearls for NEET-PG:** * **Most Common Cause:** Portal Hypertension (leading to congestive splenomegaly). * **Other Causes:** Sickle Cell Anemia, Hemochromatosis, and Leukemia. * **Imaging:** On MRI, they show a characteristic **"blooming effect"** on Gradient Echo (GRE) sequences due to the paramagnetic properties of iron. * **Composition:** Fibrous tissue + Hemosiderin (Iron) + Calcium salts. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 75-76.

Question 1

What is diapedesis?

Accepted Answer

Immigration of leukocytes through the endothelial gap to the site of inflammation

Answer

Immigration of leukocytes through the basement membrane

Answer

Aggregation of platelets at the site of inflammation

Answer

Auto-digestion of cells

Question 2

Which cells are primarily affected by HIV?

Accepted Answer

CD4 cells

Answer

CD8 cells

Answer

T cells

Answer

Plasma cells

Question 3

Autoimmunity is caused by which of the following mechanisms?

Accepted Answer

Defective negative selection of T-cells in the thymus

Answer

The pressure of forbidden clones

Answer

Expression of cryptic antigens

Answer

Inappropriate expression of MHC proteins

Question 4

A phenotypically normal woman with difficulties in conceiving was found to have three Barr bodies on karyotype analysis, with no translocations or large deletions. Her karyotype would be best represented by which one of the following?

Accepted Answer

48 XXXX

Answer

48 XXXXY

Answer

46 XX

Answer

48 XXXY

Question 5

Chromosomal non-disjunction is responsible for all of the following conditions EXCEPT:

Accepted Answer

Neurofibromatosis type 1

Answer

Down's syndrome

Answer

Prader-Willi syndrome

Answer

Angelman syndrome

Question 6

Integrins are associated with all of the following processes except:

Accepted Answer

Rolling

Answer

Adhesion

Answer

Arrest

Answer

Transmigration of cells

Question 7

MIC-2 is a marker of:

Accepted Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Dermatofibrous protruberans

Answer

Alveolar cell sarcoma

Question 8

Migratory thrombophlebitis is seen in which of the following conditions?

Accepted Answer

Disseminated cancer

Answer

Rheumatic heart disease

Answer

Libman-Sacks endocarditis

Answer

All of the above

Question 9

What is LATS?

Accepted Answer

IgG

Answer

IgM

Answer

Glycoprotein

Answer

IgA

Question 10

Gamna Gandy bodies contain hemosiderin and what else?

Accepted Answer

Ca++

Answer

Na+

Answer

Mg++

Answer

Cl-

General Pathology — MCQs

General Pathology — MCQs

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