General Pathology — MCQs

General Pathology Indian Medical PG Practice Questions and MCQs

Question 91: In which mode of inheritance are males more commonly affected than females?

A. Autosomal dominant
B. Autosomal recessive
C. X-linked dominant (Correct Answer)
D. None of these

Explanation: **Explanation:** The correct answer is **X-linked dominant**. This mode of inheritance follows a specific pattern where the gene responsible for the trait or disorder is located on the X chromosome. **Why X-linked dominant is correct:** In X-linked dominant inheritance, a single copy of the mutated gene is sufficient to cause the disease. **Females** have two X chromosomes (XX), while **males** have only one (XY). Because females have two chances to inherit a normal X chromosome, they often show milder symptoms or variable expressivity due to **Lyonization** (random X-inactivation). However, because females have two X chromosomes, they are statistically more likely to inherit the affected X from either parent. Conversely, a male will always be affected if he inherits the mutated X from his mother. Therefore, in the general population, X-linked dominant disorders are **more frequently observed in females**, though often with less severity than in males. **Why other options are incorrect:** * **Autosomal Dominant:** These traits affect both sexes equally as the gene is located on non-sex chromosomes (autosomes). Only one copy of the gene is needed for expression. * **Autosomal Recessive:** These also affect both sexes equally. Two copies of the mutated gene are required for the phenotype to manifest. * **X-linked Recessive:** In this mode, **males are more commonly affected** than females because males are hemizygous; they lack a second X chromosome to mask the recessive mutation [1]. **NEET-PG High-Yield Pearls:** * **Classic Example:** Vitamin D-resistant rickets (Hypophosphatemic rickets) and Alport Syndrome (though inheritance can vary). * **Key Distinguishing Feature:** An affected father will pass the trait to **all of his daughters** but **none of his sons** (since he provides the Y chromosome to sons) [1]. * **Lethality:** Many X-linked dominant conditions (e.g., Incontinentia Pigmenti, Rett Syndrome) are often lethal in males *in utero*, further skewing the clinical prevalence toward females. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, p. 151.

Question 92: Hypertrophy is a result of what process?

A. Increased production of cellular proteins (Correct Answer)
B. Growth factor-driven proliferation of mature cells
C. Reprogramming of stem cells
D. Decreased protein synthesis and increased protein degradation in cells

Explanation: **Explanation:** **Hypertrophy** is defined as an increase in the size of cells, resulting in an increase in the size of the organ [2]. Unlike hyperplasia, there is no formation of new cells; instead, cells become larger [1]. 1. **Why Option A is Correct:** Hypertrophy is driven by an **increased production of cellular proteins** [1]. When a cell is subjected to increased workload or hormonal stimulation (e.g., cardiac muscle in hypertension or skeletal muscle in exercise), mechanical sensors and growth factors trigger signal transduction pathways. This leads to the induction of genes that increase the synthesis of structural proteins and organelles, allowing the cell to handle the increased demand [1]. 2. **Why Other Options are Incorrect:** * **Option B (Proliferation of mature cells):** This describes **Hyperplasia**, which is an increase in the *number* of cells [2]. * **Option C (Reprogramming of stem cells):** This is the mechanism behind **Metaplasia**, where one adult cell type is replaced by another cell type better suited to a new stressor. * **Option D (Decreased synthesis and increased degradation):** This describes the mechanism of **Atrophy**, which results in a decrease in cell size and number. **High-Yield NEET-PG Pearls:** * **Pure Hypertrophy:** Occurs in permanent cells that cannot divide, such as **cardiac myocytes** and **skeletal muscle**. * **Hypertrophy + Hyperplasia:** Occurs in cells capable of division, such as the **pregnant uterus** (smooth muscle) [1]. * **Molecular Switch:** In cardiac hypertrophy, there is often a switch from adult to fetal forms of proteins (e.g., ̑-myosin heavy chain is replaced by the more energy-efficient ̒-form). * **Pathological Example:** Left Ventricular Hypertrophy (LVH) due to systemic hypertension. **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. 45-46. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 85-88.

Question 93: What is the color of hemosiderin?

A. Black
B. Brown (Correct Answer)
C. Blue
D. Yellow

Explanation: **Explanation:** **Hemosiderin** is an endogenous, iron-containing pigment derived from the breakdown of hemoglobin [2]. When red blood cells are phagocytosed by macrophages (e.g., after a hemorrhage or in chronic congestion), hemoglobin is broken down into heme and globin. The iron from heme is stored in the form of **ferritin micelles**, which aggregate to form **hemosiderin** [2]. 1. **Why Brown is correct:** Under a light microscope (H&E stain), hemosiderin appears as **golden-yellow to brown**, granular or crystalline intracellular pigment [1], [3]. It is most commonly seen in the spleen, liver, and bone marrow, or at sites of previous hemorrhage (like a resolving bruise) [2]. 2. **Why other options are incorrect:** * **Black:** This is characteristic of **carbon (anthracotic) pigment**, commonly found in the lungs and hilar lymph nodes of smokers or city dwellers. * **Blue:** While hemosiderin itself is brown, it turns **Prussian Blue** when treated with **Perls’ reaction** (potassium ferrocyanide) [1]. This is a classic histochemical stain used to differentiate iron from other pigments like melanin or lipofuscin. * **Yellow:** While often described as "golden-yellow," the definitive pathological description for NEET-PG purposes is **Brown** [1]. Pure yellow pigments are more characteristic of **Bilirubin** (which is non-granular) [2]. **NEET-PG High-Yield Pearls:** * **Prussian Blue Stain:** The gold standard for identifying hemosiderin (Iron) [1]. * **Heart Failure Cells:** These are hemosiderin-laden macrophages found in the alveoli of patients with chronic left-sided heart failure. * **Lipofuscin vs. Hemosiderin:** Lipofuscin is the "wear and tear" pigment (yellow-brown) but is **negative** for Prussian Blue stain. * **Hemochromatosis:** A systemic overload of iron leading to massive hemosiderin deposition and organ damage (Bronze diabetes) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 854-855. [2] 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. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 394-395.

Question 94: All of the following is an example of squamous metaplasia except:

A. Cervix in case of chronic irritation
B. Respiratory tract in case of smoking
C. Stone in bile ducts
D. Esophagus in gastric reflux (Correct Answer)

Explanation: **Explanation:** Metaplasia is a reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type, usually to better withstand chronic irritation or stress [2]. **Why Option D is the Correct Answer:** In **Gastroesophageal Reflux Disease (GERD)**, the normal **stratified squamous epithelium** of the lower esophagus is replaced by **columnar epithelium** (with goblet cells) to resist the acidic environment. This is known as **Barrett’s Esophagus** [1]. Since the change is *from* squamous *to* columnar, it is an example of **Columnar Metaplasia**, not squamous metaplasia. **Analysis of Incorrect Options (Examples of Squamous Metaplasia):** * **Option A (Cervix):** Chronic irritation or changes in pH at the transformation zone cause the simple columnar epithelium of the endocervix to change into stratified squamous epithelium. * **Option B (Respiratory Tract):** Chronic smoking causes the pseudostratified ciliated columnar epithelium of the trachea/bronchi to be replaced by stratified squamous epithelium [2], [3]. While more resilient, it loses mucus secretion and ciliary clearance [2]. * **Option C (Bile Ducts/Gallbladder):** The presence of stones (calculi) provides mechanical irritation, causing the normal columnar lining to undergo squamous metaplasia. Similar changes occur in the bladder (due to *Schistosoma* or stones) and salivary ducts. **High-Yield NEET-PG Pearls:** 1. **Most common type:** Squamous metaplasia is the most common epithelial metaplasia. 2. **Mechanism:** It occurs due to the **reprogramming of stem cells** (not transdifferentiation of mature cells). 3. **Vitamin A Deficiency:** Can induce squamous metaplasia in the respiratory tract and eyes (Xerophthalmia). 4. **Pre-cancerous potential:** While metaplasia is reversible, persistent irritation can lead to dysplasia and eventually **Squamous Cell Carcinoma** (in the lungs/cervix) [3] or **Adenocarcinoma** (in Barrett’s esophagus) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 348-349. [2] 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, p. 49. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 723.

Question 95: The retinoblastoma gene is located on which chromosome?

A. Chromosome 6
B. Chromosome 9
C. Chromosome 13 (Correct Answer)
D. Chromosome 21

Explanation: **Explanation:** The **Retinoblastoma (RB1) gene** is a classic tumor suppressor gene located on the **long arm of chromosome 13 (specifically 13q14)** [1], [2]. It plays a critical role in cell cycle regulation by controlling the G1 to S phase transition. The RB protein, in its hypophosphorylated state, binds to the E2F transcription factor, preventing the cell from entering the S phase. Loss of both alleles (Knudson’s "Two-Hit" Hypothesis) leads to uncontrolled cell proliferation, resulting in retinoblastoma and osteosarcoma [1]. **Analysis of Options:** * **Chromosome 13 (Correct):** Home to the *RB1* gene and the *BRCA2* gene [1]. Deletions at 13q14 are the genetic hallmark of retinoblastoma [2]. * **Chromosome 6:** Associated with the Major Histocompatibility Complex (MHC/HLA) genes and the *HFE* gene (Hemochromatosis). * **Chromosome 9:** Notable for the *CDKN2A* (p16) tumor suppressor gene and the *ABL* proto-oncogene (involved in the 9;22 Philadelphia chromosome translocation). * **Chromosome 21:** Associated with Down Syndrome (Trisomy 21) and the *APP* (Amyloid Precursor Protein) gene, but not the RB gene. **High-Yield Clinical Pearls for NEET-PG:** * **Knudson’s Two-Hit Hypothesis:** First described using the RB gene; hereditary cases have one germline mutation (1st hit) and one somatic mutation (2nd hit) [1], [2]. * **Morphology:** Look for **Flexner-Wintersteiner rosettes** (pathognomonic for retinoblastoma). * **Associated Tumors:** Patients with germline *RB1* mutations have a high risk of developing **Osteosarcoma** later in life. * **Key Regulator:** RB is inactivated by phosphorylation via **Cyclin D/CDK4** complexes. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 300. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 227-228.

Question 96: Severe generalized edema is called as:

A. Pitting edema.
B. Anasarca. (Correct Answer)
C. Myxoedema
D. Dependent edema

Explanation: ### Explanation **Correct Answer: B. Anasarca** **Anasarca** is defined as severe, generalized edema characterized by widespread swelling of the subcutaneous tissues and accumulation of fluid in body cavities (such as the pleural space, pericardium, and peritoneum) [1]. It is typically caused by a profound decrease in plasma oncotic pressure (e.g., Nephrotic syndrome, liver failure) or severe salt and water retention (e.g., Congestive Heart Failure) [2]. **Analysis of Incorrect Options:** * **A. Pitting Edema:** This is a *physical sign* rather than a term for severity or distribution [2]. It occurs when pressure applied to the swollen area leaves a persistent indentation. While anasarca is usually pitting, not all pitting edema is generalized (it can be localized to the ankles). * **C. Myxoedema:** This refers to a specific type of non-pitting, "doughy" edema caused by the deposition of glycosaminoglycans (mucopolysaccharides) in the dermis, classically seen in **hypothyroidism**. * **D. Dependent Edema:** This describes the *distribution* of fluid influenced by gravity [2]. In ambulatory patients, it appears in the lower limbs; in bedridden patients, it appears in the sacral region. It is a feature of congestive heart failure but does not imply the "generalized" severity that anasarca does. **High-Yield NEET-PG Pearls:** * **Transudate vs. Exudate:** Edema fluid in anasarca is typically a **transudate** (low protein, low specific gravity <1.012). * **Starling’s Forces:** The primary mechanisms of edema include increased capillary hydrostatic pressure, decreased plasma osmotic pressure (hypoalbuminemia), lymphatic obstruction, and sodium retention [2]. * **Renal Edema:** Classically starts in loose connective tissue areas, such as **periorbital edema** (puffiness of eyelids), before progressing to anasarca [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 126-127. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 124-126.

Question 97: Necrosis with putrefaction is called as:

A. Desiccation
B. Gangrene (Correct Answer)
C. Liquefaction
D. Coagulative necrosis

Explanation: **Explanation:** **Gangrene** is defined as a form of tissue death (necrosis) that is followed by **putrefaction** [1]. The underlying mechanism involves initial ischemic necrosis (usually coagulative) which then becomes superinfected by saprophytic bacteria (such as *Clostridium perfringens*). These bacteria decompose the organic matter, leading to the characteristic foul smell and black discoloration associated with gangrene [1]. **Analysis of Options:** * **Desiccation (A):** This refers to the state of extreme dryness or the process of drying out. While "Dry Gangrene" involves desiccation of tissues (mummification), it is the result of ischemia without significant bacterial putrefaction [1]. * **Liquefaction (C):** This is a type of necrosis where the tissue is transformed into a liquid viscous mass. While it occurs in "Wet Gangrene" due to the action of hydrolytic enzymes from bacteria and neutrophils, liquefaction alone does not define the clinical entity of gangrene. * **Coagulative Necrosis (D):** This is the most common pattern of necrosis (seen in all organs except the brain) where cell outlines are preserved. It is the *precursor* to gangrene, but without the addition of putrefaction, it remains simple necrosis. **High-Yield NEET-PG Pearls:** * **Dry Gangrene:** Primarily due to arterial occlusion; features "Mummification" and a clear **line of demarcation** [1]. * **Wet Gangrene:** Occurs in moist tissues (e.g., bowel, mouth, cervix); lacks a clear line of demarcation and has high bacterial activity [1]. * **Gas Gangrene:** A specific type of wet gangrene caused by *Clostridium* species, characterized by crepitus (gas bubbles in tissue) [1]. * **Key Distinction:** Necrosis + Putrefaction = Gangrene. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 103-104.

Question 98: Which of the following is a true neoplasm of functional cementoblasts?

A. Periapical cemental dysplasia
B. Familial cemental dysplasia
C. Benign cementoblastoma (Correct Answer)
D. Hypercementosis

Explanation: **Explanation:** The correct answer is **Benign Cementoblastoma**. This condition is classified as the only **true neoplasm** of cementoblasts. It is a rare, odontogenic tumor characterized by the proliferation of functional cementoblasts that form a mass of cementum-like tissue attached directly to the root of a tooth. **Why the other options are incorrect:** * **Periapical Cemental Dysplasia (PCD):** This is a **reactive/dysplastic** process, not a neoplasm. It typically occurs at the apex of vital mandibular anterior teeth and progresses through osteolytic, cementoblastic, and mature stages. * **Familial Cemental Dysplasia:** Also known as Gigantiform Cementoma, this is a hereditary **dysplastic** condition involving multiple quadrants of the jaws. While aggressive, it is considered a developmental/dysplastic anomaly rather than a true neoplasm. * **Hypercementosis:** This is a **non-neoplastic** deposition of excessive cementum on the roots of teeth. It is often associated with local factors (inflammation, trauma) or systemic conditions like Paget’s disease of bone. **High-Yield Clinical Pearls for NEET-PG:** * **Radiographic Hallmark:** Benign cementoblastoma appears as a well-defined **radiopaque mass** attached to the tooth root (usually the mandibular first molar), surrounded by a characteristic **radiolucent halo**. * **Clinical Feature:** Unlike many other odontogenic tumors, it is often associated with **localized pain and swelling**. * **Key Association:** The involved tooth remains **vital**, but the tumor is physically attached to the root, often requiring extraction of the tooth along with the lesion.

Question 99: When does the tensile strength of a wound start to increase?

A. Immediate suture of the wound
B. 3 to 4 days
C. 7 to 10 days (Correct Answer)
D. 6 months

Explanation: **Explanation:** The tensile strength of a healing wound is directly related to the synthesis and cross-linking of **Type I collagen**. 1. **Why 7 to 10 days is correct:** During the first 3–5 days (the "lag phase"), the wound has almost no strength as it is dominated by inflammation and the formation of granulation tissue [1]. Around the end of the first week (day 7–10), **collagen synthesis** by fibroblasts peaks. This marks the definitive onset of the increase in tensile strength [2]. By the end of the first week, the wound typically reaches approximately **10%** of the strength of unwounded skin [2]. 2. **Analysis of Incorrect Options:** * **A. Immediate suture:** Sutures provide mechanical closure but do not contribute to the biological "tensile strength" of the tissue itself. Sutured wounds have about 70% of the strength of normal skin solely due to the sutures [2]. * **B. 3 to 4 days:** This is the "lag phase" or "exudative phase." While fibroblasts are arriving, they have not yet produced enough organized collagen to significantly increase the wound's inherent strength [1]. * **D. 6 months:** By this time, the wound is in the late remodeling phase. While strength continues to increase through collagen cross-linking and the shift from Type III to Type I collagen, it usually plateaus at about **70–80%** of original strength by 3 months [2]. It does not "start" at 6 months. **High-Yield NEET-PG Pearls:** * **Maximum Strength:** A healed wound rarely exceeds **70-80%** of the strength of original, unwounded skin [2]. * **Collagen Switch:** In early healing, Type III collagen is predominant; in mature scars, it is replaced by **Type I collagen**. * **Vitamin C and Copper:** Essential cofactors for collagen cross-linking (prolyl hydroxylase and lysyl oxidase), critical for developing tensile strength. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 119-121.

Question 100: On electron microscopy, amyloid characteristically exhibits which of the following?

A. Beta-pleated sheets
B. Hyaline globules
C. 7.5-10 nm fibrils (Correct Answer)
D. 20-25 nm fibrils

Explanation: **Explanation:** **Amyloid** is a pathologic proteinaceous substance deposited in the extracellular space [1], [2]. Regardless of the clinical setting or chemical composition, all amyloid deposits share a common physical structure [2]. **1. Why Option C is Correct:** On **Electron Microscopy (EM)**, amyloid is characterized by continuous, non-branching, linear fibrils with a diameter of **7.5 to 10 nm** [1], [2]. These fibrils are arranged in a random, felt-like pattern. This ultrastructural appearance is the "gold standard" for identifying amyloid at the microscopic level and is responsible for its unique staining properties. **2. Why the Other Options are Incorrect:** * **Option A (Beta-pleated sheets):** While amyloid does form a cross-beta-pleated sheet configuration, this refers to its **secondary protein structure** (detected via X-ray crystallography and Infrared spectroscopy), not its appearance on electron microscopy [2]. * **Option B (Hyaline globules):** This is a non-specific light microscopy finding seen in various conditions (e.g., Russell bodies in plasma cells or Alpha-1 antitrypsin deficiency). It does not describe the ultrastructure of amyloid. * **Option D (20-25 nm fibrils):** This diameter is too large for amyloid. For comparison, microtubules are typically ~25 nm in diameter. **NEET-PG High-Yield Pearls:** * **Light Microscopy:** Appears as extracellular, amorphous, eosinophilic (pink) material (Hyaline-like). * **Congo Red Stain:** Shows characteristic **Apple-green birefringence** under polarized light (due to the beta-pleated sheet structure) [2]. * **Composition:** 95% Fibril proteins and 5% P-component (glycoproteins) [2]. * **Common Types:** **AL** (Light chain - Plasma cell dyscrasias), **AA** (Serum Amyloid Associated - Chronic inflammation), and **Aβ** (Alzheimer’s disease). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 135-136. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 264-269.

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Cell Injury and Cell Death

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Adaptations of Cellular Growth

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Acute and Chronic Inflammation

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Tissue Repair and Wound Healing

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Hemodynamic Disorders

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Genetic Disorders

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Environmental Pathology

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Nutritional Diseases

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Molecular Basis of Disease

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