General Pathology Practice Questions

Q: A patient presents with hepatomegaly and joint pain. Investigations suggest abnormal intracellular accumulation of macromolecules such as lipids or glycoconjugates. Which cellular organelle is primarily responsible for this accumulation?

Lysosome. ***Lysosome*** - **Lysosomes** contain hydrolytic enzymes responsible for breaking down complex macromolecules like lipids and glycosaminoglycans; their deficiency leads to **lysosomal storage diseases**. - Accumulation of undigested substrate in organs like the liver (**hepatomegaly**) and connective tissue (**joint pain**) is a hallmark feature of these disorders, such as **Gaucher disease** or **Mucopolysaccharidoses**. *Golgi apparatus* - The **Golgi apparatus** is primarily involved in the post-translational modification, packaging, and sorting of proteins and lipids for secretion or delivery to other organelles. - Defects here typically result in altered **protein trafficking** or secretion rather than the massive intracellular accumulation of undigested macromolecular substances. *Mitochondria* - **Mitochondria** are primarily responsible for **ATP production** via oxidative phosphorylation and the regulation of apoptosis. - Dysfunction commonly manifests as **myopathy**, lactic acidosis, or neurological deficits, rather than the storage of complex macromolecules. *Peroxisome* - **Peroxisomes** are responsible for the breakdown of **very-long-chain fatty acids (VLCFAs)** via beta-oxidation and the catabolism of hydrogen peroxide. - Accumulation here corresponds to conditions like **Zellweger syndrome** or **X-linked adrenoleukodystrophy**, which primarily cause severe neurological symptoms rather than the classic lysosomal storage pattern.

Q: A child presents with hepatosplenomegaly, anemia, and bone pain. Histopathological examination reveals macrophages with a “crumpled tissue paper” appearance due to cerebroside accumulation. Deficiency of which enzyme is responsible for this condition?

β-Glucocerebrosidase. ***β-Glucocerebrosidase*** - This condition is **Gaucher disease**, which is caused by a deficiency of the **β-glucocerebrosidase** enzyme, leading to the accumulation of **glucocerebroside** in lysosomes. - The characteristic **Gaucher cells** demonstrate an accumulation of substrate giving them a pathognomonic **crumpled tissue paper** appearance in the spleen, liver, and bone marrow. *Hexosaminidase A* - Deficiency of this enzyme leads to **Tay-Sachs disease**, characterized by **progressive neurodegeneration** and a **cherry-red macula**. - Cells in Tay-Sachs exhibit **onion-skin** lysosomal inclusions, distinct from the Gaucher cell inclusions. *Sphingomyelinase* - Deficiency of sphingomyelinase leads to **Niemann-Pick disease** (Type A and B). - Patients with Niemann-Pick typically present with **hepatosplenomegaly** and **cherry-red macula**, but the cells demonstrate **foam cells** (lipid-laden macrophages) rather than crumpled tissue paper. *Arylsulfatase A* - Deficiency of arylsulfatase A results in **metachromatic leukodystrophy**, a demyelinating disease of the central and peripheral nervous system. - Clinical presentation involves **ataxia**, **dementia**, and **seizures** rather than the viseo-visceral manifestations like hepatosplenomegaly found in this patient.

Q: A 28-year-old male presents with low-grade fever, night sweats, weight loss, and productive cough for 8 weeks. Chest X-ray shows a right upper lobe opacity with cavitation. Sputum AFB smear is positive. The lung biopsy histology is shown in Image 3. The type of necrosis seen at the centre of the lesion in this image is also characteristically found in which of the following conditions?

A. Histoplasmosis. ***Histoplasmosis*** - The clinical presentation and positive AFB smear indicate **Mycobacterium tuberculosis**, which causes **caseous necrosis**, characterized by a friable, white, "cheese-like" appearance. - **Histoplasmosis**, a fungal infection, is also a classic cause of **granulomatous inflammation** with central **caseous necrosis**, making it morphologically similar to tuberculosis. *Liquefactive necrosis in cerebral abscess* - **Liquefactive necrosis** is characterized by the total digestion of dead cells, resulting in a liquid viscous mass, common in **central nervous system** infarcts and bacterial abscesses. - Unlike caseous necrosis, it does not maintain a dry, granular appearance but rather forms a **liquid pus** or cystic space. *Coagulative necrosis in myocardial infarction* - **Coagulative necrosis** preserves the basic **structural outline** of the dead tissue for several days, typical of hypoxic cell death in all organs except the brain. - It lacks the amorphous, granular, and acellular "cheese-like" debris that defines the **caseating granulomas** seen in the provided scenario. *Fat necrosis in acute pancreatitis* - **Fat necrosis** refers to focal areas of fat destruction typically resulting from the release of activated **pancreatic lipases** into the peritoneum. - It is characterized by **saponification**, where fatty acids combine with calcium to produce macroscopic **chalky white deposits**, distinct from the granulomatous pattern of TB.

Question 1

A patient presents with hepatomegaly and joint pain. Investigations suggest abnormal intracellular accumulation of macromolecules such as lipids or glycoconjugates. Which cellular organelle is primarily responsible for this accumulation?

Accepted Answer

Lysosome

Answer

Golgi apparatus

Answer

Mitochondria

Answer

Peroxisome

Question 2

A child presents with hepatosplenomegaly, anemia, and bone pain. Histopathological examination reveals macrophages with a “crumpled tissue paper” appearance due to cerebroside accumulation. Deficiency of which enzyme is responsible for this condition?

Accepted Answer

β-Glucocerebrosidase

Answer

Hexosaminidase A

Answer

Sphingomyelinase

Answer

Arylsulfatase A

Question 3

Which statement correctly describes incomplete penetrance?

Accepted Answer

Multiple individuals in one generation are affected but the next generation is entirely spared

Answer

All children of an affected parent will be clinically affected

Answer

The disease will not manifest in any individual of the next generation

Answer

Alternate generations of pedigree are affected by the condition

Question 4

A 45-year-old male presents with nephrotic syndrome, frothy urine, and bilateral pedal edema. Serum albumin is 2.1 g/dL. Urinalysis shows 4+ proteinuria. Renal biopsy is performed. The electron microscopy image is shown (Image 1), demonstrating subepithelial electron-dense deposits along the glomerular basement membrane. Which of the following best explains the pathogenesis of the glomerular injury seen in this condition?

Accepted Answer

A. In situ immune complex formation involving anti-PLA2R antibodies targeting podocyte antigens with complement-mediated injury

Answer

B. Circulating immune complex deposition in the mesangium activating the alternative complement pathway

Answer

C. Anti-GBM antibody binding to type IV collagen alpha-3 chain causing linear IgG deposits along the basement membrane

Answer

D. T-cell mediated cytokine release causing podocyte foot process effacement without immune complex deposition

Question 5

A 28-year-old male presents with low-grade fever, night sweats, weight loss, and productive cough for 8 weeks. Chest X-ray shows a right upper lobe opacity with cavitation. Sputum AFB smear is positive. The lung biopsy histology is shown in Image 3. The type of necrosis seen at the centre of the lesion in this image is also characteristically found in which of the following conditions?

Accepted Answer

A. Histoplasmosis

Answer

D. Fat necrosis in acute pancreatitis

Answer

B. Liquefactive necrosis in cerebral abscess

Answer

C. Coagulative necrosis in myocardial infarction

General Pathology — MCQs

General Pathology — MCQs

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