General Pathology Practice Questions

Q: The ocular basement membrane is stained with which of the following?

Periodic acid-Schiff. **Explanation:** The correct answer is **Periodic acid-Schiff (PAS)**. **Why PAS is the correct answer:** Basement membranes (including those in the eye, such as Descemet’s membrane and the lens capsule) are rich in **neutral mucopolysaccharides** and **Type IV collagen**. The PAS stain works by oxidizing the carbon-carbon bonds in glucose residues to create aldehydes, which then react with the Schiff reagent to produce a deep magenta/pink color. Because the ocular basement membranes are exceptionally thick and carbohydrate-rich, PAS is the gold-standard histopathological stain for visualizing them [1]. **Analysis of Incorrect Options:** * **Alcaine blue (Alcian Blue):** This stain is used to detect **acidic mucopolysaccharides** (like hyaluronic acid or chondroitin sulfate). It is commonly used to identify goblet cells in intestinal metaplasia (Barrett’s esophagus) but does not specifically highlight the basement membrane. * **Giemsa stain:** This is a differential stain primarily used for hematology (blood smears) and detecting specific pathogens like *Chlamydia*, *Plasmodium*, and *Leishmania*. * **Methylene blue:** This is a simple basic dye used to highlight nuclei or to identify morphology in fecal leukocytes; it lacks the specificity for the complex carbohydrates of the basement membrane. **NEET-PG High-Yield Pearls:** * **PAS Positive structures:** Basement membranes, Glycogen (diastase sensitive), Fungi (cell walls), and Amoeba. * **Descemet’s Membrane:** This is the basement membrane of the corneal endothelium and is one of the thickest in the body, making it intensely PAS-positive [1]. * **Silver Stains (GMS/Jones):** These are also used for basement membranes (especially in the kidney), but PAS is the classic choice for ocular histology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Eye, p. 1328.

Q: True rosettes are seen in all of the following except:

Thecoma. **Explanation:** The term **"True Rosettes"** in pathology refers to specific circular arrangements of tumor cells around a central lumen or a fibrillar core. These are characteristic histological markers for primitive neuroectodermal and neuroepithelial tumors. **Why Thecoma is the correct answer:** A **Thecoma** is a benign sex cord-stromal tumor of the ovary [1]. Histologically, it is composed of spindle-shaped cells laden with lipid (theca cells) and does not exhibit any rosette formation [1]. Rosettes are a feature of neuroectodermal differentiation, which is absent in mesenchymal/stromal tumors like thecomas. **Analysis of Incorrect Options:** * **Neuroblastoma:** Characterized by **Homer-Wright rosettes**, which are "pseudorosettes" because they contain a central hub of neuropil (fibrillar material) rather than a true lumen. However, in the context of many exams, both true and pseudorosettes are grouped under the broad umbrella of "rosettes" seen in small round blue cell tumors. * **Retinoblastoma:** Classically shows **Flexner-Wintersteiner rosettes**, which are considered "True Rosettes" because they contain a central empty lumen. * **Medulloblastoma:** Frequently demonstrates **Homer-Wright rosettes**, similar to neuroblastoma, representing primitive neural differentiation. **NEET-PG High-Yield Pearls:** 1. **Flexner-Wintersteiner Rosettes:** True lumen; seen in Retinoblastoma, Pineoblastoma, and Ependymoma. 2. **Homer-Wright Rosettes:** No lumen (fibrillar center); seen in Neuroblastoma, Medulloblastoma, and PNET. 3. **Perivascular Pseudorosettes:** Cells arranged around a blood vessel; the hallmark of **Ependymoma**. 4. **Call-Exner Bodies:** Small fluid-filled spaces between granulosa cells; pathognomonic for **Granulosa Cell Tumor** (often confused with rosettes). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Female Genital Tract Disease, pp. 481-482.

Q: Major basic proteins are produced by which type of cell?

Eosinophil. **Explanation:** **Major Basic Protein (MBP)** is the primary constituent of the crystalline core of **Eosinophil** granules. It is a highly cytotoxic polypeptide that plays a critical role in the body's defense against helminthic parasites by damaging the parasite's tegument. * **Why Eosinophil is Correct:** Eosinophils contain specialized secondary granules consisting of a crystalloid core (containing MBP) and a surrounding matrix (containing Eosinophil Cationic Protein, Eosinophil Peroxidase, and Eosinophil-Derived Neurotoxin). MBP is potent enough to cause degranulation of mast cells and basophils and can also cause epithelial damage in conditions like bronchial asthma [1]. * **Why Other Options are Incorrect:** * **Lymphocytes:** These are agranulocytes involved in adaptive immunity (T-cells and B-cells) and do not contain MBP. * **Neutrophils:** Their primary granules (azurophilic) contain myeloperoxidase and defensins, while secondary granules contain lactoferrin and collagenase. They do not produce MBP. * **Basophils:** While they share some mediators with eosinophils, their granules primarily contain histamine, heparin, and chondroitin sulfate. **High-Yield Clinical Pearls for NEET-PG:** 1. **Charcot-Leyden Crystals:** These are hexagonal, needle-like crystals found in the sputum of asthma patients (Curschmann spirals) and result from the breakdown of eosinophil membranes (specifically **Galectin-10**). 2. **Eosinophilia:** Classically seen in **PACMAN**: **P**arasitic infections, **A**sthma/Allergies, **C**hurg-Strauss syndrome, **M**yeloproliferative disorders, **A**ddison’s disease, and **N**eoplasia (Hodgkin Lymphoma). 3. MBP is a potent trigger for **histamine release** from mast cells, linking eosinophilic inflammation to immediate hypersensitivity reactions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 688-689.

Q: Which of the following patterns is seen in DNA electrophoresis?

Apoptosis. **Explanation:** The correct answer is **Apoptosis**. The hallmark of apoptosis on DNA electrophoresis is a characteristic **"Step-ladder pattern."** **1. Why Apoptosis is correct:** During apoptosis, specific calcium- and magnesium-dependent endonucleases (caspase-activated DNase) cleave the DNA at internucleosomal linker regions [1]. Since DNA is wrapped around histones in regular intervals of approximately 180–200 base pairs, this enzymatic cleavage results in DNA fragments of varying lengths that are multiples of 180–200 bp. When these fragments are separated by electrophoresis, they form a distinct "step-ladder" appearance. **2. Why the other options are incorrect:** * **Necrosis:** Unlike the programmed cleavage in apoptosis, necrosis involves random, uncontrolled degradation of DNA and the nucleus (karyolysis). This results in a diffuse, continuous distribution of DNA fragments of all sizes, appearing as a **"Smear pattern"** on electrophoresis. * **Dysplasia and Metaplasia:** These are cellular adaptations or pre-neoplastic changes involving alterations in cell size, shape, organization, or phenotype. They do not involve the specific DNA fragmentation patterns seen in programmed cell death [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Apoptosis:** Step-ladder pattern (Internucleosomal cleavage). * **Necrosis:** Smear pattern (Random cleavage). * **Gold Standard for Apoptosis:** The **TUNEL assay** (Terminal deoxynucleotidyl transferase dUTP nick end labeling) is used to detect these DNA fragments in situ. * **Annexin V:** A marker used to detect phosphatidylserine on the outer leaflet of the plasma membrane, another early marker of apoptosis [1]. **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. 63-65.

Question 1

The ocular basement membrane is stained with which of the following?

Accepted Answer

Periodic acid-Schiff

Answer

Alcaine blue

Answer

Giemsa stain

Answer

Methylene blue

Question 2

Which of the following is a labile cell?

Accepted Answer

Surface epithelium

Answer

Cardiac cell

Answer

Liver parenchymal cell

Answer

Vascular endothelial cells

Question 3

True rosettes are seen in all of the following except:

Accepted Answer

Thecoma

Answer

Neuroblastoma

Answer

Retinoblastoma

Answer

Medulloblastoma

Question 4

A 60-year-old diabetic female presented with a burning sensation aggravated by spicy food. Intraoral examination revealed multiple periodontal abscesses and a keratotic area in a lace pattern with occasional erosive areas within the lace pattern. What histological feature would be expected?

Accepted Answer

Saw-tooth rete ridges

Answer

Elongated rete ridges

Answer

Flattened rete ridges

Answer

Bulbous rete ridges

Question 5

Major basic proteins are produced by which type of cell?

Accepted Answer

Eosinophil

Answer

Lymphocyte

Answer

Neutrophil

Answer

Basophil

Question 6

What is the most efficient bactericidal system of neutrophils?

Accepted Answer

H2O2-MPO-Halide

Answer

NADPH oxidase

Answer

Lysozyme

Answer

Reactive nitrogen species

Question 7

Down syndrome is due to non-disjunction of which chromosome?

Accepted Answer

Chromosome 21

Answer

Chromosome 18

Answer

Chromosome 11

Answer

Chromosome 15

Question 8

Dystrophic calcification is commonly seen in which of the following conditions?

Accepted Answer

Atheromatous plaque

Answer

Hyperparathyroidism

Answer

Vitamin D deficiency

Answer

Renal disease

Question 9

Polycythemia is associated with all of the following cancers except?

Accepted Answer

Prostate cancer

Answer

Stomach cancer

Answer

Liver cancer

Answer

Renal cell cancer

Question 10

Which of the following patterns is seen in DNA electrophoresis?

Accepted Answer

Apoptosis

Answer

Necrosis

Answer

Dysplasia

Answer

Metaplasia

General Pathology — MCQs

General Pathology — MCQs

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