Irreversible injury in myocardium occurs at ?
Which of the following is a sign of reversible injury in alcoholic liver disease?
Which of the following is not a germ cell tumor?
Caseous necrosis is seen in -
Which of the following cell types is classified as a labile cell?
Which of the following are examples of trinucleotide repeat mutations?
Gastric carcinoma is associated with all of the following EXCEPT:
Centrilobular necrosis of the liver may be seen with?
Linitis plastica is a type of ?
What are Councilman bodies and in which condition are they typically observed?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 11: Irreversible injury in myocardium occurs at ?
- A. 30 minutes (Correct Answer)
- B. 5 hours
- C. 1 minute
- D. 1 hour
Explanation: ***30 minutes*** - Irreversible injury to **myocardial cells** typically begins **at approximately 20-30 minutes of ischemia** [1]. - This time frame represents the critical threshold where cellular damage, including **mitochondrial dysfunction** and **sarcolemmal rupture**, becomes too severe for recovery even with reperfusion [2]. - Beyond this point, cells lose membrane integrity and undergo **coagulative necrosis** [2]. *1 minute* - Myocardial cells can tolerate **ischemia** for a short period, with reversible changes occurring within the first few minutes [4]. - At 1 minute, the injury is still entirely **reversible**, and cells can fully recover if blood flow is restored [5]. - Changes at this stage include depletion of ATP and accumulation of metabolites [5]. *1 hour* - While significant **irreversible damage** has occurred by this time, the onset of irreversibility is earlier, around the 20-30 minute mark [1]. - By 1 hour, a substantial portion of the ischemic myocardium would have undergone **necrosis**, but the critical threshold was crossed 30 minutes earlier [2]. *5 hours* - By 5 hours, nearly all myocardial tissue that was subjected to continuous **ischemia** would have experienced **irreversible injury** and necrosis [3]. - This duration is well beyond the initial window for irreversible changes, indicating extensive and widespread cell death [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 140-142. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 554-556. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 548-550. [5] 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. 61-62.
Question 12: Which of the following is a sign of reversible injury in alcoholic liver disease?
- A. Cytoplasmic vacuole (Correct Answer)
- B. Pyknosis (nuclear shrinkage)
- C. Loss of cell membrane integrity
- D. Nuclear karyolysis (nuclear dissolution)
Explanation: ***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.
Question 13: Which of the following is not a germ cell tumor?
- A. Embryonal carcinoma
- B. Endodermal sinus
- C. Seminoma
- D. Leydig cell tumor (Correct Answer)
Explanation: ***Leydig cell tumor*** - Leydig cell tumors are classified as **sex-cord stromal tumors**, not germ cell tumors [1]. - These tumors are derived from **Leydig cells** which produce androgens, affecting the endocrine function rather than germ cell lineage [1]. *Endodermal sinus* - Endodermal sinus tumors, or **yolk sac tumors**, are indeed germ cell tumors characterized by **alpha-fetoprotein (AFP)** production [2]. - They typically arise in the testis or ovaries and are known for rapid growth and aggressiveness. *Embryonal carcinoma* - Embryonal carcinoma is a type of **germ cell tumor** commonly associated with elevated levels of **beta-hCG** [2]. - It primarily affects the testes in males and can occur in the ovaries, and it is known for its aggressive behavior. *Seminoma* - Seminomas are classic examples of **germ cell tumors**, noted for their sensitivity to radiation and chemotherapy [3]. - They usually present with **increased beta-hCG** levels and can coexist with non-seminomatous germ cell tumors [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 510-514. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lower Urinary Tract and Male Genital System, pp. 979-980. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lower Urinary Tract and Male Genital System, pp. 980-982.
Question 14: Caseous necrosis is seen in -
- A. Tuberculosis (Correct Answer)
- B. CMV infection
- C. Treponemal infection
- D. Staphylococcal infection
Explanation: ***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.
Question 15: Which of the following cell types is classified as a labile cell?
- A. Liver parenchymal cells
- B. Vascular smooth muscle cells
- C. Surface epithelium (Correct Answer)
- D. Neurons
Explanation: ***Surface epithelium*** - Surface epithelium is classified as **labile tissue**, meaning it undergoes constant regeneration due to its high turnover rate [1]. - Cells in this tissue are typically found in areas that experience frequent damage or abrasion, such as the skin and lining of the intestines. *Cardiac cell* - Cardiac cells are considered **permanent cells**, as they do not undergo significant regeneration after injury or damage. - Damage to cardiac cells typically leads to **fibrosis** rather than repair of the original tissue. *Liver parenchymal cell* - Liver parenchymal cells are categorized as **stable cells**, which can regenerate but do so under specific circumstances, such as injury. - They have a slower turnover rate compared to labile cells and do not constantly renew under normal conditions. *Vascular endothelial cells* - Vascular endothelial cells are considered **stable cells** as well, typically maintaining a stable population but capable of regeneration following injury. - They do not have the same rapid turnover and regeneration capability as labile cells do, especially under normal physiological conditions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 113-115.
Question 16: Which of the following are examples of trinucleotide repeat mutations?
- A. Friedreich ataxia
- B. Fragile X syndrome
- C. Huntington's chorea
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Fragile X syndrome**, **Friedreich ataxia**, and **Huntington's chorea** are all well-known examples of genetic disorders caused by trinucleotide repeat expansions [1]. - The mutations involve an abnormal increase in the number of repetitions of a specific three-nucleotide sequence in the DNA [1]. *Fragile X syndrome* - This condition is caused by an expansion of the **CGG repeat** in the **FMR1 gene** on the X chromosome [1]. - The expansion leads to hypermethylation and silencing of the gene, impairing the production of fragile X mental retardation protein [1]. *Friedreich ataxia* - This is an autosomal recessive neurodegenerative disorder caused by an expansion of the **GAA repeat** in an intron of the **frataxin gene (FXN)**. - The repeat expansion interferes with transcription, leading to reduced frataxin protein levels. *Huntington's chorea* - This is an autosomal dominant neurodegenerative disorder caused by an expansion of the **CAG repeat** in the **huntingtin gene (HTT)**. - The expanded polyglutamine tract in the huntingtin protein leads to protein misfolding and neuronal damage, particularly in the striatum [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 177-181.
Question 17: Gastric carcinoma is associated with all of the following EXCEPT:
- A. Over expression of C-met
- B. Inactivation of p53
- C. Over expression of C-erb
- D. Activation of RAS (Correct Answer)
Explanation: ***Activation of RAS*** - **RAS mutations** are relatively uncommon in gastric carcinoma compared to other gastrointestinal malignancies. While KRAS mutations can occur in approximately 10-15% of gastric cancers (particularly intestinal type), they are **far less frequent** than in **pancreatic adenocarcinoma** (~90%) or **colorectal carcinoma** (~40%). - In the context of gastric carcinoma, RAS pathway alterations are **not considered a major oncogenic driver** compared to the other molecular changes listed, making this the **LEAST characteristically associated** alteration. *Inactivation of p53* - **Inactivation of the p53 tumor suppressor gene** is one of the most frequent molecular events in gastric carcinoma, occurring in approximately **50-60% of cases**. - Loss of p53 function leads to genomic instability, uncontrolled cell proliferation, and resistance to apoptosis, contributing significantly to **tumorigenesis** and **poor prognosis**. *Over expression of C-met* - **Overexpression of C-MET**, a receptor tyrosine kinase for hepatocyte growth factor (HGF), is commonly observed in gastric carcinoma (30-40% of cases) and is strongly linked to **tumor growth**, **invasion**, and **metastasis**. - C-MET amplification and overexpression promote cell proliferation, survival, migration, and angiogenesis, making it an important **therapeutic target** in advanced gastric cancer. *Over expression of C-erb* - **Overexpression of C-erbB-2 (HER2/neu)** is found in approximately **10-20% of gastric adenocarcinomas**, particularly the intestinal type. - HER2 amplification or overexpression is a significant **prognostic and predictive biomarker**, and is specifically targeted by **trastuzumab** (Herceptin) therapy in HER2-positive advanced gastric cancer, improving survival outcomes.
Question 18: Centrilobular necrosis of the liver may be seen with?
- A. Arsenic
- B. Ethanol
- C. CCl4 (Correct Answer)
- D. Phosphorus
Explanation: ***CCl4*** - **Carbon tetrachloride (CCl4)** is the **classic and prototypical** hepatotoxin that causes **centrilobular (zone 3) necrosis**. - The **centrilobular zone (zone 3)** is particularly vulnerable due to its high concentration of **cytochrome P450 enzymes**, which metabolize CCl4 into **toxic free radicals (trichloromethyl radicals)**. - This is the **most characteristic** cause of centrilobular necrosis in toxicology and is the preferred answer for exam purposes. *Ethanol* - **Ethanol** can also cause **centrilobular necrosis** in **alcoholic hepatitis**, as zone 3 is most susceptible to hypoxic injury and oxidative stress. - However, alcoholic liver disease presents with a **spectrum of changes** including steatosis (earliest), hepatitis with ballooning degeneration and Mallory-Denk bodies, and eventual cirrhosis. - While centrilobular necrosis occurs in alcoholic hepatitis, **CCl4 remains the prototype** for pure centrilobular necrosis in exam contexts. *Phosphorus* - **Elemental phosphorus** toxicity causes **periportal (zone 1) necrosis**, which is the opposite pattern from centrilobular necrosis. - It also causes widespread fatty change and hemorrhagic necrosis within the liver. *Arsenic* - **Arsenic poisoning** causes **diffuse/generalized hepatocellular necrosis** and cholestasis, rather than the specific centrilobular pattern. - Chronic exposure is associated with non-cirrhotic portal fibrosis and portal hypertension.
Question 19: Linitis plastica is a type of ?
- A. Benign ulcer
- B. GIST
- C. Manifestation of gastric cancer (Correct Answer)
- D. Plastic-like appearance of stomach lining
Explanation: ***Diffuse carcinoma of stomach*** - Linitis plastica is a specific type of **gastric cancer** characterized by **thickening of the stomach wall**, leading to a rigid, non-distensible abdomen [1]. - It often presents with **significant weight loss** and **early satiety**, distinguishing it from other stomach conditions. *Benign ulcer* - Benign ulcers do not cause the **extensive wall thickening** or **desmoplastic response** seen in linitis plastica [1]. - They typically heal with treatment and are associated with typical ulcer symptoms, unlike the progressive nature of linitis plastica. *Plastic like lining of stomach* - While linitis plastica describes a **plastic-like appearance**, it is not classified as a mere lining change but rather a sign of underlying **malignancy** [1]. - This option misrepresents it as a benign condition rather than a serious **stomach adenocarcinoma**. *GIST* - Gastrointestinal stromal tumors (GIST) are **soft tissue tumors** of mesenchymal origin, differing fundamentally from the **invasive** characteristics of linitis plastica [2]. - GISTs typically present with **mass lesions** in the GI tract, not the diffuse rigidity seen in linitis plastica [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 779-780. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 779.
Question 20: What are Councilman bodies and in which condition are they typically observed?
- A. Wilson's disease
- B. Ballooning degeneration of hepatocytes
- C. Acute viral hepatitis (Correct Answer)
- D. Alcoholic liver disease
Explanation: **Option G*****Acute viral hepatitis*** - Councilman bodies are **characteristic histological findings** in acute viral hepatitis, associated with apoptotic hepatocytes [1]. - They represent **necrosis** of liver cells, which is commonly seen during the acute phase of viral infections affecting the liver [1]. *Alcoholic cirrhosis* - While liver damage is present, Councilman bodies are not typical; they are more associated with acute conditions rather than the chronic nature of cirrhosis. - **Fibrosis** and **bridging necrosis** are evident in alcoholic cirrhosis, distinct from the **acute necrotic changes** seen in viral hepatitis. *Ballooning of cells - Damaged cells show diffuse swelling known as ballooning degeneration.* - Ballooning degeneration indicates **cellular swelling**, often noted in conditions like steatosis or alcoholic liver disease, but does not lead to the formation of Councilman bodies. - These changes are different from the **pyknotic or karyolytic changes** associated with Councilman bodies in acute infections. *Hepatic cell necrosis - The necrosis is usually focal or centirzonal.* - This refers to various types of necrosis in the liver but does not specifically indicate the presence of Councilman bodies, which are linked with apoptotic cells. - While necrosis is common in hepatic pathology, Councilman bodies are particularly associated with **viral hepatitis**. *Wilson's disease* - Although it causes liver damage, it typically results in **copper accumulation** and associated features, not specifically Councilman bodies in its pathology. - The findings in Wilson's disease include **hepatocellular degeneration** without the distinct apoptotic features seen in **acute viral hepatitis**. Option F*Autoimmune hepatitis* - This condition may cause liver cell damage and necrosis but does not typically show Councilman bodies in its histological profile. - It primarily shows **interface hepatitis** and **lymphocytic infiltration**, contrasting with the **apoptotic bodies** seen in acute viral scenarios. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 386-387.