General Pathology Practice Questions

Q: All of the following are intermediate filaments except?

Cadherin. **Explanation:** The cytoskeleton of a cell consists of three main components: microfilaments (actin), microtubules (tubulin), and **intermediate filaments (IFs)**. Intermediate filaments (10 nm) provide structural stability to cells and are tissue-specific markers. **Why Cadherin is the correct answer:** **Cadherins** are not cytoskeletal filaments; they are **transmembrane cell adhesion molecules** (CAMs) [1]. They play a critical role in cell-cell adhesion by forming "adherens junctions" and "desmosomes." They are calcium-dependent proteins that link the internal cytoskeleton of one cell to another, but they do not function as intermediate filaments themselves [1]. **Why the other options are incorrect:** * **Lamin (Option A):** These are type V intermediate filaments found in the **nucleus** (nuclear lamina) of all nucleated cells. They provide structural support to the nuclear envelope. * **Vimentin (Option C):** This is the most common type III intermediate filament. It is the characteristic marker for cells of **mesenchymal origin** (e.g., fibroblasts, endothelium, and most sarcomas). * **Desmin (Option D):** Also a type III intermediate filament, desmin is specific to **muscle cells** (skeletal, cardiac, and smooth muscle). It links myofibrils together. **High-Yield Clinical Pearls for NEET-PG:** * **Cytokeratin:** IF marker for **Epithelial** cells (used to diagnose Carcinomas). * **GFAP (Glial Fibrillary Acidic Protein):** IF marker for **Astrocytes** and ependymal cells (used to diagnose Gliomas). * **Neurofilaments:** IF marker for **Neurons** (used to diagnose Pheochromocytoma or Neuroblastoma). * **Mallory Hyaline bodies** (seen in alcoholic liver disease) are composed of tangled **cytokeratin** intermediate filaments. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 23-24.

Q: In which type of necrosis is tissue architecture preserved?

Coagulative necrosis. **Explanation:** **Coagulative necrosis** is the correct answer because it is characterized by the **preservation of basic tissue architecture** for at least several days [1]. The underlying mechanism involves the denaturation of not only structural proteins but also enzymatic proteins. This denaturation blocks the proteolysis (digestion) of the dead cells; as a result, firm, opaque, "ghost-like" cell outlines persist without nuclei until phagocytes eventually clear the debris [1]. **Why other options are incorrect:** * **Liquefaction necrosis:** In contrast to coagulative necrosis, the tissue is completely digested by hydrolytic enzymes, transforming it into a liquid viscous mass (pus). The architecture is entirely lost. This is typically seen in focal bacterial infections or brain infarcts. * **Fat necrosis:** This refers to focal areas of fat destruction, typically resulting from the release of activated pancreatic lipases [1]. It results in the formation of "chalky white" calcium deposits (saponification), which destroys the original cellular structure [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Type:** Coagulative necrosis is the most common pattern of necrosis. * **Etiology:** It is characteristic of **hypoxic/ischemic death** in all solid organs **except the brain**. * **Microscopic Hallmark:** "Ghost cells" (cells with preserved outlines but loss of nuclei/organelles) [1]. * **Macroscopic Hallmark:** The affected area is typically firm and pale (infarct) [1]. * **Key Exception:** Ischemia in the **Central Nervous System (CNS)** results in liquefaction necrosis, not coagulative necrosis. **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. 53-55.

Q: Which interleukin is responsible for causing pyrexia?

IL1. **Explanation:** **IL-1 (Interleukin-1)** is the primary endogenous pyrogen responsible for inducing fever (pyrexia) [1]. When the body encounters pathogens or inflammatory stimuli, macrophages and other immune cells release IL-1. This cytokine travels through the bloodstream to the hypothalamus, where it stimulates the synthesis of **Prostaglandin E2 (PGE2)** via the induction of the cyclooxygenase (COX) enzyme [1]. PGE2 then resets the hypothalamic thermostat to a higher level, resulting in fever. **Analysis of Options:** * **IL-1 (Correct):** Known as the "master" endogenous pyrogen. Along with TNF-α, it is the most potent inducer of the febrile response [1]. * **IL-6:** While IL-6 is a major mediator of the **acute-phase response** (stimulating the liver to produce CRP, fibrinogen, and hepcidin), it is considered a secondary pyrogen compared to the direct action of IL-1 [1]. * **Interferon-gamma (IFN-γ):** Primarily involved in activating macrophages (Type IV hypersensitivity) and antiviral responses; it does not play a primary role in the central induction of fever. * **Interferon-alpha (IFN-α):** Mainly functions in antiviral defense by inhibiting viral replication in neighboring cells. **High-Yield Clinical Pearls for NEET-PG:** * **Pyrogen Hierarchy:** The most important endogenous pyrogens are **IL-1, TNF-α, and IL-6** [1]. * **Exogenous Pyrogens:** The most common example is **LPS (Lipopolysaccharide)** from Gram-negative bacteria, which triggers the release of IL-1. * **Mechanism of Action:** Antipyretics like Paracetamol and NSAIDs reduce fever by inhibiting the COX enzyme, thereby blocking the synthesis of PGE2 in the hypothalamus [1]. * **Acute Phase Reactants:** Remember that **IL-6** is the chief stimulator for the production of C-Reactive Protein (CRP) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 110-111.

Q: All of the following are seen in Thymoma except?

Hyperalbuminemia. Hypogammaglobulinemia [5] is also known as Good’s Syndrome; this triad consists of thymoma, hypogammaglobulinemia, and low B-cell counts [3, 5], leading to increased susceptibility to infections. Analysis of Incorrect Options: Myasthenia Gravis (Option D): This is the most common association, seen in approximately 30–45% of thymoma patients. It is caused by autoantibodies against acetylcholine receptors (AChR) [1, 2] at the neuromuscular junction. Red Cell Aplasia (Option C): Pure Red Cell Aplasia (PRCA) is seen in about 5–10% of cases. Most common mediastinal tumor: Thymoma (specifically in the anterior mediastinum) [3]. Histology: Look for a mixture of neoplastic epithelial cells and non-neoplastic T-lymphocytes (thymocytes) [4]. Staging: The Masaoka Staging System is used to determine the prognosis based on capsular invasion [4]. **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. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1237-1238. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 571-572. [4] 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. 634-635. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 549-551.

Question 1

Storiform pattern of tumor cells in histopathology is seen in which of the following tumors?

Accepted Answer

Fibrous histiocytoma

Answer

Retinoblastoma

Answer

Rhabdomyosarcoma

Answer

Medulloepithelioma

Question 2

All of the following are intermediate filaments except?

Accepted Answer

Cadherin

Answer

Lamin

Answer

Vimentin

Answer

Desmin

Question 3

Which mutation is most commonly associated with prostate carcinoma?

Accepted Answer

GPST1

Answer

p16/INK4a

Answer

PTEN

Answer

APC

Question 4

In which type of necrosis is tissue architecture preserved?

Accepted Answer

Coagulative necrosis

Answer

Liquefaction necrosis

Answer

Fat necrosis

Answer

All of the above

Question 5

Which interleukin is responsible for causing pyrexia?

Accepted Answer

IL1

Answer

IL6

Answer

Interferon gamma

Answer

Interferon alpha

Question 6

Which of the following is an example of a non-dividing/permanent cell?

Accepted Answer

Neuron

Answer

Hepatocyte

Answer

Lymphocyte

Answer

Respiratory epithelium

Question 7

Metastatic calcification is seen in:

Accepted Answer

Normal tissues

Answer

Cysts

Answer

Atheroma

Answer

Infarcts

Question 8

All of the following statements about the typical features of a periapical granuloma are true EXCEPT?

Accepted Answer

It shows evidence of local antibody production

Answer

It consists of proliferating granulation tissue

Answer

It can form only if the periapical bone is resorbed

Answer

It results from immunologically mediated tissue damage

Question 9

Which of the following does not occur in lysosomal storage disorders?

Accepted Answer

No neurological deficit

Answer

Increased number and size of lysosomes

Answer

Accumulation of polyubiquinated proteins

Answer

Apoptosis defects

Question 10

All of the following are seen in Thymoma except?

Accepted Answer

Hyperalbuminemia

Answer

Hypogammaglobulinemia

Answer

Red cell aplasia

Answer

Myasthenia gravis

General Pathology — MCQs

General Pathology — MCQs

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