General Pathology Practice Questions

Q: Caseous necrosis is seen in -

Tuberculosis. ***Tuberculosis*** - **Caseous necrosis** is the **pathognomonic** and **most characteristic** form of necrosis seen in **tuberculosis (TB)** caused by *Mycobacterium tuberculosis* [1]. - It appears as a **cheesy, friable, granular material** in the center of **tuberculous granulomas** (tubercles) [1], [2]. - The unique **lipid-rich cell wall** of *M. tuberculosis* combined with the host's **type IV hypersensitivity reaction** results in this distinctive pattern of tissue destruction [2]. - This is a **classic histopathological hallmark** of TB and is essential for diagnosis [2]. *Treponemal infection* - **Syphilis**, caused by *Treponema pallidum*, causes **gummatous necrosis**, NOT caseous necrosis [3]. - Gummas have a **rubbery consistency** and different histological appearance compared to the cheesy, friable caseous necrosis. - While syphilis produces granulomatous inflammation, the necrosis pattern is distinctly different from TB [3]. *CMV infection* - **Cytomegalovirus (CMV)** infection typically causes **coagulative necrosis** with **cytopathic effects** (enlarged cells with intranuclear and intracytoplasmic inclusions - "owl's eye" appearance) [3]. - Does NOT produce caseous necrosis. *Staphylococcal infection* - **Staphylococcal infections** (e.g., *Staphylococcus aureus*) cause **liquefactive necrosis** leading to **abscess formation** [3]. - Dead cells are enzymatically digested into **liquid pus**, completely different from the solid, cheesy appearance of caseous 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, p. 55. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 383-384. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, p. 360.

Q: What is the major fibril protein associated with Primary Amyloidosis?

Immunoglobulin Light Chain. ***AL*** - In Primary Amyloidosis, **AL amyloid** is derived from immunoglobulin light chains produced by **plasma cell dyscrasias** [1]. - This type of amyloidosis is commonly associated with conditions like **multiple myeloma** or monoclonal gammopathy [1]. *Transthyretin* - This protein is associated with **Familial Amyloid Polyneuropathy** and **Senile Systemic Amyloidosis**, not Primary Amyloidosis. - Transthyretin amyloidosis (ATTR) results from **mutations** or **aging**, contributing to different clinical presentations than AL. *AA* - AA amyloidosis is secondary and occurs due to **chronic inflammatory** conditions, such as rheumatoid arthritis or chronic infections. - It is not the main fibril protein in **Primary Amyloidosis**, which is specifically linked to **light chains**. *Procalcitonin* - Procalcitonin is a **biomarker** used primarily for diagnosing bacterial infections, particularly sepsis, and is not involved in amyloidogenesis. - It does not relate to amyloidosis and is not a component of amyloid fibrils. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 266-267.

Q: Which of the following is a sign of reversible injury in alcoholic liver disease?

Cytoplasmic vacuole. ***Cytoplasmic vacuole*** - The presence of **cytoplasmic vacuoles** in liver cells indicates fatty change, which is a **reversible injury** in alcoholic liver disease [1][2]. - This injury allows the liver to recover if **alcohol consumption** is ceased, highlighting its reversible nature [1]. *Nuclear karyolysis* - **Nuclear karyolysis** signifies severe cellular damage and necrosis, indicating an irreversible process [2]. - This feature involves the dissolution of the nucleus, which does not align with reversible injury. *Loss of cell membrane* - Loss of the **cell membrane** indicates irreversible damage, leading to cell death rather than a reversible condition [2]. - This change is associated with significant cellular impairment, contrary to the concept of recovery. *Pyknosis* - **Pyknosis**, the condensation of chromatin in the nucleus, suggests irreversible cellular injury and impending necrosis [2]. - It is often a precursor to cell death and is not indicative of reversible damage in liver pathology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 848-850. [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. 51-53.

Q: Which of the following translocations is not associated with Down syndrome?

t(11;14). ***t (11: 14)*** - The **t(11;14) translocation** is commonly associated with **mantle cell lymphoma**, a B-cell non-Hodgkin lymphoma, and is not a cause of Down syndrome. - This translocation leads to the overexpression of the **cyclin D1 gene**, located on chromosome 11, which promotes cell growth and proliferation. *t (14; 21)* - This is a common **Robertsonian translocation** involving chromosomes 14 and 21, which results in an extra copy of chromosome 21 material [1]. - Individuals with this translocation can have **Down syndrome** because their cells end up with the equivalent of three copies of chromosome 21 [1]. *t (21; 21)* - This translocation is another type of **Robertsonian translocation** where two chromosome 21s fuse. - This specific translocation is rare and results in an extra copy of chromosome 21, leading to **Down syndrome** with a high recurrence risk in offspring. *t (15: 21)* - This is a **Robertsonian translocation** involving chromosomes 15 and 21, resulting in an extra copy of chromosome 21 material. - This translocation is a known cause of **Down syndrome** due to the dosage imbalance of genes on chromosome 21 [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 169-172.

Q: What condition is the Lendrum stain primarily used to diagnose?

Amniotic fluid embolism. ***Amniotic fluid embolism*** - The **Lendrum stain** (specifically the modified Lendrum stain) is used to detect **fetal squamous cells** and **mucin** in maternal lung tissue, which are markers for amniotic fluid embolism [1]. - It helps confirm the diagnosis of this rare but severe obstetric emergency characterized by the entry of **amniotic fluid** into the maternal circulation [1]. *Air embolism* - Air embolism is diagnosed based on the presence of **gas bubbles** in blood vessels, often visualized by imaging or directly during autopsy, not by a specific tissue stain [1]. - Histologically, air emboli lead to characteristic foam-like structures in vascular lumens, but no specific stain highlights the air itself. *Fat embolism* - Fat embolism is diagnosed by the presence of **fat globules** in pulmonary capillaries and other organs, typically stained with **oil-soluble dyes like Oil Red O** or Sudan stains on frozen sections. - The Lendrum stain is designed for mucin and keratin, not neutral lipids like fat. *Thromboembolism* - Thromboembolism involves **blood clots** that occlude vessels and is diagnosed using routine H&E staining, which shows fibrin, platelets, and red blood cells [1]. - Special stains like **phosphotungstic acid-hematoxylin (PTAH)** or **Martius scarlet blue (MSB)** may be used for fibrin, but the Lendrum stain is specifically designed for amniotic fluid components, not thrombi. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 323-324.

Q: Cells most sensitive to hypoxia are?

Neurons. ***Neurons*** - Neurons have a very high metabolic rate and an **absolute requirement for oxygen** and glucose to maintain their complex electrochemical functions and ionic gradients. - Due to their lack of significant energy reserves and high metabolic demand, they can sustain **irreversible damage within minutes** (typically 3-5 minutes) of complete oxygen deprivation. *Myocardial cells* - While myocardial cells are highly susceptible to hypoxia and can undergo **ischemic necrosis** (e.g., in a myocardial infarction), they can often tolerate oxygen deprivation for somewhat longer periods than neurons due to some anaerobic metabolic capacity. - Significant damage to myocardial cells usually occurs after **20-30 minutes of severe ischemia**. *Hepatocytes* - Hepatocytes (liver cells) are relatively **resilient to hypoxia** compared to neurons, possessing significant metabolic flexibility and capacity for regeneration. - They can endure **longer periods of oxygen deprivation** before irreversible damage occurs, often hours. *Renal tubular epithelial cells* - Renal tubular epithelial cells are generally **sensitive to hypoxia**, especially those in the medulla, due to their high metabolic activity for reabsorption and secretion. - They are a common target for **acute tubular necrosis** in ischemic injury but generally have a **higher tolerance than neurons**, with damage becoming widespread after tens of minutes to an hour of severe ischemia.

Q: Lines of Zahn occur in -

Thrombus. ***Thrombus*** - **Lines of Zahn** are alternating layers of **platelets** (lighter bands) and **red blood cells** (darker bands) that are characteristic of a **thrombus** formed in flowing blood. - Their presence indicates that the clot was formed in a vessel where there was **blood flow** *Infarct* - An **infarct** is an area of **ischemic necrosis** caused by occlusion of either the arterial supply or venous drainage in a particular tissue. - While a thrombus can cause an infarct, an infarct itself does not contain Lines of Zahn; rather, it is the consequence of the thrombus. *Embolus* - An **embolus** is a detached intravascular solid, liquid, or gaseous mass that is carried by the blood to a site distant from its origin. - An embolus can be a fragment of a thrombus and therefore could contain Lines of Zahn, but the primary structure where these lines are formed is the stationary thrombus within a vessel. *Postmortem clot* - A **postmortem clot** forms after death and is typically gelatinous, poorly attached to the vessel wall, and has a dark red dependent portion (due to red cell settling) and a yellowish upper portion (like "chicken fat"). - It does not exhibit the layered architecture of platelets and red blood cells seen in **Lines of Zahn**, as there is no active blood flow or coagulation process at play.

Q: When differentiated cells transform to form cells characteristic of other tissues, the process is called as -

Trans-differentiation. ***Trans-differentiation*** - **Trans-differentiation** refers to the direct conversion of one differentiated cell type into another differentiated cell type without entering a pluripotent stem cell state. - This process is achieved by altering the **gene expression profile** of existing cells to adopt the characteristics of a different lineage. *De-differentiation* - **De-differentiation** is the process where a specialized cell loses its specific characteristics and reverts to a more primitive or stem cell-like state. - This is often observed in certain disease processes, like cancer, or in response to injury where cells regain limited proliferative capacity. *Re-differentiation* - **Re-differentiation** typically describes a cell that has undergone de-differentiation and then differentiates again into a new or its original cell type. - This process is often seen in tissue repair, where progenitor cells proliferate and then re-differentiate to replace damaged tissue. *Sub-differentiation* - **Sub-differentiation** is not a standard or recognized term in cell biology or developmental biology to describe the transformation of stem cells into other tissue types. - The term does not have a defined meaning within the context of cellular lineage alterations.

Q: Male to male transmission is seen in -

Autosomal dominant diseases. ***Autosomal dominant diseases*** - **Autosomal dominant** inheritance patterns involve a gene located on one of the **autosomes**, meaning it is not sex-linked. - Therefore, a father carrying an autosomal dominant gene can pass it to both sons and daughters with a **50% probability** for each child. - **Male-to-male transmission** is a hallmark feature that helps distinguish autosomal dominant from X-linked inheritance patterns. *Autosomal recessive* - **Autosomal recessive** diseases require **two copies** of the mutated gene (one from each parent) for the disease to manifest. - While a father can pass a recessive allele to his son, male-to-male transmission of the **disease phenotype** requires the mother to also be at least a carrier, making it not a defining feature of this inheritance pattern. - The key characteristic is horizontal pattern (affected siblings) rather than vertical transmission. *X-linked dominant* - In **X-linked dominant** inheritance, affected fathers **cannot** transmit the trait to their sons because sons inherit their **X chromosome** from their mother and their Y chromosome from their father. - All daughters of an affected father will inherit the affected X chromosome and thus the disease. - **Absence of male-to-male transmission** is a key distinguishing feature. *Mitochondrial disease* - **Mitochondrial diseases** are inherited exclusively from the **mother** to all her children, regardless of their sex. - Fathers with mitochondrial disease cannot transmit the condition to any of their children. - This shows **maternal inheritance only**, with no paternal transmission possible.

Question 1

Caseous necrosis is seen in -

Accepted Answer

Tuberculosis

Answer

CMV infection

Answer

Treponemal infection

Answer

Staphylococcal infection

Question 2

Dystrophic calcification is seen in

Accepted Answer

Atheromatous plaque

Answer

Vitamin A intoxication

Answer

Milk alkali syndrome

Answer

Hyperparathyroidism

Question 3

What is the major fibril protein associated with Primary Amyloidosis?

Accepted Answer

Immunoglobulin Light Chain

Answer

Amyloid Associated protein (AA)

Answer

Procalcitonin (PCT)

Answer

Transthyretin (TTR)

Question 4

Which of the following is a sign of reversible injury in alcoholic liver disease?

Accepted Answer

Cytoplasmic vacuole

Answer

Pyknosis (nuclear shrinkage)

Answer

Loss of cell membrane integrity

Answer

Nuclear karyolysis (nuclear dissolution)

Question 5

Which of the following translocations is not associated with Down syndrome?

Accepted Answer

t(11;14)

Answer

t(21;21)

Answer

t(14;21)

Answer

t(15;21)

Question 6

What condition is the Lendrum stain primarily used to diagnose?

Accepted Answer

Amniotic fluid embolism

Answer

Air embolism

Answer

Fat embolism

Answer

Thromboembolism

Question 7

Cells most sensitive to hypoxia are?

Accepted Answer

Neurons

Answer

Myocardial cells

Answer

Hepatocytes

Answer

Renal tubular epithelial cells

Question 8

Lines of Zahn occur in -

Accepted Answer

Thrombus

Answer

Embolus

Answer

Infarct

Answer

Postmortem clot

Question 9

When differentiated cells transform to form cells characteristic of other tissues, the process is called as -

Accepted Answer

Trans-differentiation

Answer

De-differentiation

Answer

Re-differentiation

Answer

Sub-differentiation

Question 10

Male to male transmission is seen in -

Accepted Answer

Autosomal dominant diseases

Answer

Autosomal recessive

Answer

X-linked dominant

Answer

Mitochondrial disease

General Pathology — MCQs

General Pathology — MCQs

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