General Pathology — MCQs

General Pathology Indian Medical PG Practice Questions and MCQs

Question 131: Which of the following is a Heredofamilial amyloidosis?

A. Alzheimer's disease
B. Multiple myeloma
C. Familial Mediterranean fever
D. Systemic senile amyloidosis (Correct Answer)

Explanation: ### Explanation **Correct Option: D (Systemic Senile Amyloidosis)** Systemic senile amyloidosis (now often termed **Wild-type ATTR**) is classified as a heredofamilial amyloidosis because it involves the deposition of **Transthyretin (TTR)** [1]. While the "senile" form typically occurs due to age-related deposition of wild-type TTR (predominantly in the heart), the category of TTR-related amyloidoses includes various **hereditary** mutations (e.g., Familial Amyloid Polyneuropathies) [5]. In the context of standard pathology classifications (like Robbins), TTR-related diseases are grouped under heredofamilial patterns [2]. **Analysis of Incorrect Options:** * **A. Alzheimer’s Disease:** This is a form of **Localized Amyloidosis**. The protein involved is **Aβ amyloid**, derived from Amyloid Precursor Protein (APP), deposited specifically in the brain [1]. * **B. Multiple Myeloma:** This is the classic cause of **Primary Amyloidosis (AL type)** [3]. It is an acquired plasma cell dyscrasia where monoclonal light chains (kappa or lambda) deposit in tissues. It is not hereditary. * **C. Familial Mediterranean Fever (FMF):** While FMF is a hereditary *disease*, the resulting amyloidosis is **Secondary (AA type)** [2]. It occurs due to chronic inflammation (autoinflammatory state) leading to high levels of Serum Amyloid Associated (SAA) protein. In many classification schemes, it is categorized primarily as Reactive/Secondary. **NEET-PG High-Yield Pearls:** * **Most common systemic amyloidosis:** AL type (associated with Plasma Cell Dyscrasias) [3]. * **Most common hereditary amyloidosis:** Familial Mediterranean Fever (AA type) [2]. * **Staining:** All amyloids show **Apple-green birefringence** under polarized light with **Congo Red** stain [4]. * **Hemodialysis-associated amyloidosis:** Involves **β2-microglobulin**, which cannot be filtered by old dialysis membranes [1]. * **Prealbumin** is the older name for Transthyretin (TTR) [5]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 266. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 267-268. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 266-267. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 264-266. [5] 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. 136-140.

Question 132: Birbeck granules are seen in which of the following conditions?

A. Histiocytosis X (Correct Answer)
B. Gaucher's Disease
C. Albinism
D. All of the above

Explanation: **Explanation:** **Birbeck granules** are the pathognomonic ultrastructural hallmark of **Langerhans Cell Histiocytosis (LCH)**, historically known as **Histiocytosis X** [1]. 1. **Why Option A is Correct:** Langerhans cells are specialized dendritic (antigen-presenting) cells [2]. Under **Electron Microscopy (EM)**, they contain unique cytoplasmic organelles called Birbeck granules [1]. These are rod-shaped, pentalaminar structures with a central striated line and a bulbous end, giving them a characteristic **"Tennis Racket" appearance** [1]. They contain the protein **Langerin (CD207)**, which is involved in endocytosis and antigen processing [1]. 2. **Why Other Options are Incorrect:** * **Gaucher’s Disease:** This is a lysosomal storage disorder characterized by "Gaucher cells"—macrophages with a **"wrinkled tissue paper"** or "crumpled silk" appearance due to the accumulation of glucocerebroside [3]. They do not contain Birbeck granules. * **Albinism:** This condition involves a defect in melanin synthesis (tyrosinase deficiency). While it affects melanocytes, it does not involve Birbeck granules, which are specific to the Langerhans cell lineage. **High-Yield Clinical Pearls for NEET-PG:** * **Immunohistochemistry (IHC) Markers for LCH:** Positive for **S-100**, **CD1a**, and **CD207 (Langerin)**. * **Clinical Presentation:** Can range from a solitary bone lesion (Eosinophilic Granuloma) to multisystem involvement (Letterer-Siwe disease). * **Hand-Schüller-Christian Disease:** A classic triad of LCH consisting of calvarial bone defects, exophthalmos, and diabetes insipidus. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 630. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 629-630. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 162-163.

Question 133: Which of the following is NOT an acute phase reactant?

A. CRP
B. Fibrinogen
C. Tissue factor (Correct Answer)
D. Serum amyloid A

Explanation: **Explanation:** Acute Phase Reactants (APRs) are proteins whose plasma concentrations increase (positive APRs) or decrease (negative APRs) by at least 25% in response to inflammation, infection, or tissue injury [1]. This systemic response is primarily mediated by cytokines like **IL-6, IL-1, and TNF-α**, which stimulate the liver to alter protein synthesis [1]. **Why Tissue Factor is the Correct Answer:** **Tissue Factor (Option C)** is a transmembrane glycoprotein constitutively expressed by subendothelial cells (like fibroblasts) and induced in monocytes/endothelial cells during inflammation. While it plays a critical role in the coagulation cascade (extrinsic pathway), it is **not** a plasma protein synthesized by the liver as part of the systemic acute phase response. Therefore, it is not classified as an acute phase reactant. **Analysis of Incorrect Options:** * **CRP (C-Reactive Protein):** A classic positive APR [1]. It acts as an opsonin, fixing complement and facilitating phagocytosis. It is a sensitive marker of systemic inflammation. * **Fibrinogen:** A positive APR that promotes coagulation and causes RBCs to form stacks (rouleaux), which is the physiological basis for an **elevated ESR** during inflammation. * **Serum Amyloid A (SAA):** A positive APR that acts as a chemotactic factor for inflammatory cells. Chronic elevation of SAA can lead to Secondary (AA) Amyloidosis. **High-Yield NEET-PG Pearls:** * **Positive APRs:** "F-C-S" (Fibrinogen, CRP, SAA), Ferritin, Haptoglobin, Ceruloplasmin, and Complement proteins (C3, C4). * **Negative APRs:** Albumin, Transferrin, and Transthyretin (Pre-albumin). These decrease during inflammation to conserve amino acids for positive APRs. * **IL-6** is the most potent stimulator of the hepatic production of acute phase reactants [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 111.

Question 134: What is an example of two alleles expressing in a heterozygous state?

A. Codominance expression (Correct Answer)
B. Dominant expression
C. Recessive expression
D. Hemizygous expression

Explanation: ### Explanation **Correct Option: A. Codominance expression** In genetics, **codominance** occurs when both alleles in a heterozygous individual are fully and equally expressed. Neither allele is dominant or recessive over the other; instead, the phenotype reflects the independent expression of both gene products. **Why the other options are incorrect:** * **B. Dominant expression:** In a heterozygous state, only the dominant allele is expressed phenotypically, while the recessive allele is masked (e.g., Marfan Syndrome) [1]. * **C. Recessive expression:** A recessive trait is only expressed in a **homozygous** state (two copies of the allele) [1]. In a heterozygote, the recessive allele remains "silent." * **D. Hemizygous expression:** This refers to having only one copy of a gene instead of the usual two. This is typically seen in males for genes located on the X-chromosome (XY), as they lack a corresponding allele on the Y-chromosome. --- ### High-Yield Clinical Pearls for NEET-PG 1. **Classic Examples of Codominance:** * **ABO Blood Group System:** An individual with genotype $I^A I^B$ expresses both A and B antigens on their red blood cells (Type AB blood). * **Alpha-1 Antitrypsin Deficiency:** The M, S, and Z alleles are codominant; a PiMZ individual produces both M and Z proteins. * **Major Histocompatibility Complex (MHC/HLA):** Both maternal and paternal HLA alleles are expressed simultaneously on cell surfaces. 2. **Incomplete Dominance vs. Codominance:** Do not confuse the two. In *incomplete dominance*, the phenotype is a "blend" or intermediate (e.g., red + white = pink), whereas in *codominance*, both traits appear distinctly. 3. **Pleiotropy:** A single gene mutation affecting multiple organ systems (e.g., Sickle Cell Anemia or Marfan Syndrome). This is a frequent "distractor" in genetics questions. **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. 53-54.

Question 135: Alpha-1-antitrypsin deficiency is a cause of which of the following conditions?

A. Congenital cystic disease
B. Neonatal hepatitis (Correct Answer)
C. Pulmonary fibrosis
D. All of the above

Explanation: **Explanation:** **Alpha-1-Antitrypsin (AAT) Deficiency** is a genetic disorder characterized by the misfolding of the AAT protein, primarily due to the **PiZZ genotype** [1]. **1. Why Neonatal Hepatitis is Correct:** AAT is synthesized in the liver. In the deficiency state (specifically the PiZ variant), a mutation causes the protein to misfold and aggregate within the endoplasmic reticulum of hepatocytes [1]. These aggregates are toxic, leading to hepatocyte destruction. In neonates, this manifests as **neonatal cholestasis or hepatitis**, which can progress to juvenile cirrhosis and hepatocellular carcinoma [1], [4]. A classic histopathological hallmark is the presence of **PAS-positive, diastase-resistant globules** in the periportal hepatocytes [1]. **2. Why Other Options are Incorrect:** * **Congenital Cystic Disease:** This is typically associated with developmental anomalies of the biliary tree (like Caroli disease) or kidneys (ADPKD), not protein misfolding disorders like AAT deficiency. * **Pulmonary Fibrosis:** AAT deficiency causes **Panacinar Emphysema**, not fibrosis [2]. The lack of AAT (a protease inhibitor) leads to unchecked elastase activity, which destroys the alveolar walls (elastic tissue), resulting in permanent enlargement of airspaces [2]. **3. NEET-PG High-Yield Pearls:** * **Inheritance:** Autosomal Codominant [1]. * **Genetics:** Gene located on **Chromosome 14** [2]. * **Lung Involvement:** Causes **Panacinar emphysema**, most severe in the **lower lobes** [2]. Smoking accelerates this damage. * **Liver Involvement:** Only occurs if the protein is misfolded and retained (PiZZ) [3]. It does not occur in the null phenotype (where no protein is produced). * **Diagnosis:** Low serum AAT levels; Phenotyping via isoelectric focusing; Liver biopsy showing PAS+ globules [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 856-858. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 683-684. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, p. 858. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 862-864.

Question 136: What is the arrangement of the nuclei in giant cells?

A. Present at the center
B. Forming a network
C. Arranged radially
D. Arranged around the periphery (Correct Answer)

Explanation: This question refers specifically to the **Langhans giant cell**, which is a hallmark of granulomatous inflammation (most commonly seen in Tuberculosis) [1]. ### **Explanation of the Correct Answer** In **Langhans giant cells**, which are formed by the fusion of epithelioid cells (activated macrophages), the nuclei are characteristically **arranged around the periphery** of the cell in a horseshoe-shaped or circular pattern [1]. This peripheral arrangement leaves the central part of the cytoplasm relatively clear or granular [1]. This morphology is a key diagnostic feature in histopathology for identifying granulomatous diseases [2]. ### **Analysis of Incorrect Options** * **A. Present at the center:** This describes **Foreign Body Giant Cells**. In these cells, nuclei are scattered irregularly or clustered in the center of the cytoplasm. They form in response to non-immunogenic foreign material (e.g., sutures, talc). * **B. Forming a network:** Nuclei in giant cells remain discrete individual units; they do not fuse to form a syncytial network. * **C. Arranged radially:** This is not a recognized pathological arrangement for nuclei in giant cells. Radial arrangements are more typical of certain fungal structures (like the Splendore-Hoeppli phenomenon). ### **High-Yield NEET-PG Pearls** * **Langhans vs. Langerhans:** Do not confuse *Langhans giant cells* (Tuberculosis/Granuloma) with *Langerhans cells* (dendritic cells in the skin containing Birbeck granules). * **Touton Giant Cells:** Nuclei are arranged in a ring, surrounded by foamy/vacuolated cytoplasm (seen in Xanthomas). * **Warthin-Finkeldey Cells:** Multinucleated giant cells with "grape-like" nuclear clusters, characteristic of **Measles**. * **Reed-Sternberg Cells:** "Owl-eye" appearance; the classic giant cell of Hodgkin Lymphoma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 109. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 383-384.

Question 137: All of the following are examples of tumor markers, except?

A. Alpha-HCG (aHCG) (Correct Answer)
B. Alpha-Feto protein
C. Thyroglobulin
D. Beta-2-microglobulin

Explanation: **Explanation:** The correct answer is **Alpha-HCG (aHCG)**. Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone consisting of two subunits: alpha (α) and beta (β). The **alpha subunit** is common to several other hormones, including LH, FSH, and TSH. Because it lacks specificity, it is not used as a tumor marker [2]. In contrast, the **beta subunit (β-HCG)** is unique to HCG and serves as a highly specific tumor marker for germ cell tumors (like choriocarcinoma and embryonal carcinoma) and gestational trophoblastic disease [2][3]. **Analysis of other options:** * **Alpha-Fetoprotein (AFP):** A classic tumor marker used for the screening and monitoring of Hepatocellular Carcinoma (HCC) and non-seminomatous germ cell tumors (specifically Yolk Sac Tumors) [1]. * **Thyroglobulin:** Produced by thyroid follicular cells, it is a specific marker used to monitor recurrence or metastasis in patients with papillary and follicular thyroid carcinomas after thyroidectomy. * **Beta-2-microglobulin:** A component of MHC Class I molecules. Elevated levels are used as a prognostic marker in B-cell lymphomas, multiple myeloma, and chronic lymphocytic leukemia (CLL). **NEET-PG High-Yield Pearls:** * **Most specific marker for HCG:** Always the **Beta** subunit [2]. * **Yolk Sac Tumor:** Characterized by elevated **AFP** and Schiller-Duval bodies [1]. * **Seminoma:** Usually has normal AFP; may have mildly elevated β-HCG (in 10-15% of cases) [3]. * **CA-125:** Marker for Serous Cystadenocarcinoma of the ovary. * **PSA (Prostate Specific Antigen):** Used for prostate cancer, though it is organ-specific, not cancer-specific [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 346. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 1035-1036. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 512-513.

Question 138: Fibrinoid necrosis may be observed in which of the following conditions?

A. Malignant Hypertension
B. Polyarteritis nodosa
C. Aschoff bodies
D. All the above (Correct Answer)

Explanation: **Explanation:** **Fibrinoid necrosis** is a specialized form of cell death characterized by the deposition of immune complexes and plasma proteins (such as fibrin) into the walls of blood vessels [2]. On H&E staining, it appears as a bright pink, "smudgy," and circumferential eosinophilic area. **Why "All the Above" is correct:** The underlying mechanism involves damage to the vessel wall, allowing plasma proteins to leak into the media. This occurs in: 1. **Malignant Hypertension:** Extreme elevation in blood pressure causes acute hemodynamic injury to the arterioles, leading to fibrinoid necrosis (arteriolosclerosis) [2]. 2. **Polyarteritis Nodosa (PAN):** This is a systemic necrotizing vasculitis [1]. Immune complex deposition in the small-to-medium-sized arteries triggers an inflammatory response that destroys the vessel wall, resulting in a classic fibrinoid appearance [1]. 3. **Aschoff Bodies:** Found in the myocardium during **Acute Rheumatic Fever**, these pathognomonic foci of inflammation contain a central area of fibrinoid necrosis surrounded by Anitschkow cells (caterpillar cells). **High-Yield Clinical Pearls for NEET-PG:** * **Appearance:** It is the only type of necrosis that is typically **microscopic** and cannot be identified on gross examination. * **Immune-Mediated:** It is frequently associated with Type III Hypersensitivity reactions (e.g., SLE, Rheumatoid Arthritis). * **Key Site:** It is primarily seen in blood vessels, except for Aschoff bodies (heart) and Rheumatoid nodules (skin/subcutaneous tissue). * **Staining:** It stains intensely with **PAS stain** and **Martius Scarlet Blue (MSB)** due to the presence of fibrin. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 517-518. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 277-278.

Question 139: Which of the following statements is not true regarding necroptosis?

A. Some amount of inflammation is present.
B. Cell membrane damage is observed.
C. Caspase 8 is involved, but caspase 9 is not involved. (Correct Answer)
D. It can be both physiological and pathological.

Explanation: **Explanation:** Necroptosis is a form of programmed cell death that is morphologically similar to necrosis (cell swelling and membrane rupture) but mechanistically similar to apoptosis (genetically programmed) [1]. **Why Option C is the correct (False) statement:** The hallmark of necroptosis is that it is **caspase-independent**. While the process is often triggered by the ligation of the TNF receptor (TNFR1) [1], it specifically occurs when **Caspase-8 is inhibited or inactivated**. Under normal conditions, Caspase-8 cleaves pro-necroptotic kinases; when Caspase-8 is absent, the **RIPK1-RIPK3 complex** (necrosome) forms, leading to MLKL phosphorylation and membrane rupture [1]. Therefore, neither Caspase-8 nor Caspase-9 is involved in the execution of necroptosis. **Analysis of other options:** * **Option A:** Unlike apoptosis, necroptosis involves the leakage of cellular contents (DAMPs) due to membrane rupture, which triggers an **inflammatory response** [1]. * **Option B:** The final step of necroptosis involves the **MLKL protein** forming pores in the plasma membrane, leading to direct cell membrane damage and lysis. * **Option C:** It occurs in **pathological** states (e.g., ischemia-reperfusion injury, viral infections like CMV, pancreatitis) and **physiological** states (e.g., formation of the mammalian bone growth plate). **High-Yield NEET-PG Pearls:** * **Key Molecule:** MLKL (Mixed Lineage Kinase Domain-like protein) is the "executioner" of necroptosis. * **The Necrosome:** Composed of RIPK1 and RIPK3 kinases [1]. * **Inhibitor:** Necrostatin-1 is a specific inhibitor of RIPK1 used in research. * **Distinction:** It is often called "caspase-independent programmed necrosis" [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. 69-71.

Question 140: Hypersensitivity pneumonitis is classically a/an?

A. Allergic reaction
B. Type II hypersensitivity
C. Immune complex mediated hypersensitivity (Correct Answer)
D. Cell mediated hypersensitivity

Explanation: **Explanation:** **Hypersensitivity Pneumonitis (HP)**, also known as extrinsic allergic alveolitis [2], is an immunologic lung disease caused by repeated inhalation of environmental antigens (e.g., thermophilic actinomycetes in Farmer’s lung). **Why Option C is Correct:** Classically, the acute phase of Hypersensitivity Pneumonitis is a **Type III (Immune Complex Mediated) Hypersensitivity** reaction. Upon re-exposure to the inhaled antigen, specific IgG antibodies (precipitins) form immune complexes that deposit in the alveolar walls, triggering complement activation and an influx of neutrophils [1]. **Analysis of Incorrect Options:** * **Option A:** While HP is an "allergic" response in the broad sense, it is not a simple Type I IgE-mediated allergy. * **Option B:** Type II involves antibodies directed against fixed cell-surface antigens (e.g., Goodpasture syndrome), which is not the mechanism here. * **Option D:** While chronic HP involves **Type IV (Cell-mediated)** hypersensitivity (leading to granuloma formation), the classic textbook classification for the initial/acute immunologic mechanism is Type III [1]. **High-Yield Pearls for NEET-PG:** * **Histology:** Characterized by the "Triad" of interstitial pneumonitis, non-caseating granulomas (in 2/3rd of cases) [1], and intra-alveolar fibrosis. * **Common Examples:** Farmer’s Lung (moldy hay), Bird Fancier’s Lung (avian proteins), and Bagassosis (moldy sugar cane) [2]. * **Key Distinction:** Unlike asthma (Type I), HP affects the **alveoli** rather than the bronchi and presents with restrictive rather than obstructive lung patterns. * **Diagnosis:** Presence of serum **precipitating antibodies (IgG)** against the offending antigen [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 701-702. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 332-333.

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