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 stain is used for glycogen?

PAS (Periodic Acid-Schiff). **Explanation:** **PAS (Periodic Acid-Schiff)** is the correct answer because it is the gold-standard histochemical stain for detecting carbohydrates, specifically **glycogen**, glycoproteins, and mucins. The mechanism involves periodic acid oxidizing the carbon-carbon bonds in glucose residues to form aldehydes, which then react with the Schiff reagent to produce a characteristic **magenta/deep pink** color. **Analysis of Incorrect Options:** * **Congo Red:** This is the specific stain for **Amyloid**. Under polarized microscopy, amyloid stained with Congo red exhibits a pathognomonic "apple-green birefringence." * **Prussian Blue (Perl’s Stain):** This is used to detect **Ferric iron ($Fe^{3+}$)**. It is clinically significant in diagnosing conditions like hemochromatosis or identifying sideroblasts and hemosiderin-laden macrophages ("heart failure cells"). * **Alcian Blue:** This stain is used for **acidic mucopolysaccharides** (glycosaminoglycans). It is frequently used to identify intestinal metaplasia (Barrett’s esophagus) where it stains goblet cells blue. **Clinical Pearls for NEET-PG:** * **Diastase Sensitivity:** To confirm that PAS-positive staining is specifically due to glycogen (and not other carbohydrates), a **Diastase** test is performed. Diastase digests glycogen; if the staining disappears after treatment, it confirms the presence of glycogen. * **PAS-Positive Structures:** Basement membranes, fungal hyphae (e.g., Candida, Histoplasma), and the thick secretions in Whipple’s disease (Tropheryma whipplei) are all PAS-positive. * **Best’s Carmine:** An older, highly specific stain for glycogen, though less commonly used today than PAS.

Q: What is considered the most severe form of Ehlers-Danlos syndrome?

Type 4. **Explanation:** **Ehlers-Danlos Syndrome (EDS)** is a heterogeneous group of inherited connective tissue disorders characterized by defects in collagen synthesis [1]. **Why Type 4 is Correct:** **Type 4 (Vascular Type)** is considered the most severe and life-threatening form of EDS. It results from a mutation in the **COL3A1 gene**, leading to deficient synthesis of **Type III collagen**. Since Type III collagen is a major structural component of blood vessels and hollow organs, patients are predisposed to spontaneous **rupture of large arteries** (e.g., aorta), **bowel perforation**, and **uterine rupture** during pregnancy [1]. These catastrophic events often lead to sudden death at a young age. **Analysis of Incorrect Options:** * **Type 1 & 2 (Classical Type):** These are caused by mutations in **Type V collagen** (COL5A1, COL5A2). While they present with significant skin hyperextensibility, "cigarette paper" scarring, and joint hypermobility, they are generally not life-threatening [1]. * **Type 8 (Periodontal Type):** This is a rare variant characterized primarily by severe early-onset periodontitis leading to premature loss of teeth and skin fragility, but it lacks the fatal systemic complications of the vascular type. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Most EDS types are Autosomal Dominant (including Types 1, 2, and 4). * **Kyphoscoliotic Type (Type 6):** Notable for lysyl hydroxylase deficiency; presents with ocular fragility (corneal rupture) [1]. * **Key Clinical Triad:** Hyperextensible skin, hypermobile joints, and fragile tissues (poor wound healing) [1]. * **Vascular EDS Sign:** Translucent skin with visible underlying veins and characteristic "aged" facial features (acrogeria). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 154-156.

Q: Which of the following is characteristic of a dental cyst?

Has a cystic lining of stratified squamous epithelium. **Explanation:** A **Dental Cyst** (also known as a **Radicular Cyst** or Periapical Cyst) is the most common inflammatory odontogenic cyst. It typically forms at the apex of a non-vital (necrotic) tooth due to inflammation following dental caries or pulpitis [1]. **1. Why Option D is correct:** The hallmark histological feature of a dental cyst is a lumen lined by **non-keratinized stratified squamous epithelium**. This lining is derived from the **Rest Cells of Malassez** (remnants of Hertwig’s epithelial root sheath) found in the periodontal ligament, which proliferate in response to inflammatory cytokines. **2. Why other options are incorrect:** * **Option A:** This describes a **Dentigerous Cyst** (Follicular Cyst). Dentigerous cysts originate from the reduced enamel epithelium and surround the crown of an unerupted tooth. * **Option B:** This describes an **Odontogenic Keratocyst (OKC)** or a Primordial Cyst. A dental cyst is attached to the root of an existing tooth rather than replacing it. * **Option C:** A "missing tooth" on an X-ray associated with a radiolucency is characteristic of a **Dentigerous Cyst** (where the tooth is impacted/unerupted). In a dental cyst, the involved tooth is present in the oral cavity but is non-vital. **NEET-PG High-Yield Pearls:** * **Rushton Bodies:** Eosinophilic, linear, or arch-shaped calcifications often found within the epithelial lining of radicular cysts. * **Radiology:** Appears as a well-defined unilocular radiolucency at the periapical region. * **Cholesterol Clefts:** Frequently seen in the cyst wall with associated multinucleated giant cells. * **Key Distinction:** Radicular cyst = Non-vital tooth; Dentigerous cyst = Unerupted tooth. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 741-742.

Question 1

All of the following are intermediate filaments except?

Accepted Answer

Cadherin

Answer

Lamin

Answer

Vimentin

Answer

Desmin

Question 2

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 3

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

Accepted Answer

Neuron

Answer

Hepatocyte

Answer

Lymphocyte

Answer

Respiratory epithelium

Question 4

Metastatic calcification is seen in:

Accepted Answer

Normal tissues

Answer

Cysts

Answer

Atheroma

Answer

Infarcts

Question 5

Which stain is used for glycogen?

Accepted Answer

PAS (Periodic Acid-Schiff)

Answer

Congo red

Answer

Prussian blue

Answer

Alcian blue

Question 6

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 7

Which of the following structures is seen in all except?

Accepted Answer

Follicular carcinoma of thyroid

Answer

Papillary carcinoma of thyroid

Answer

Serous cystadenoma of ovary

Answer

Meningioma

Question 8

What is considered the most severe form of Ehlers-Danlos syndrome?

Accepted Answer

Type 4

Answer

Type 1

Answer

Type 2

Answer

Type 8

Question 9

Which of the following is characteristic of a dental cyst?

Accepted Answer

Has a cystic lining of stratified squamous epithelium

Answer

Occurs from the reduced enamel epithelium

Answer

Replaces the tooth to which it is attached

Answer

Is frequently seen with a missing tooth on the X-ray

Question 10

BRAF gene mutation is seen in which of the following conditions?

Accepted Answer

Melanoma

Answer

Breast carcinoma

Answer

Osteosarcoma

Answer

Prostate carcinoma

General Pathology — MCQs

General Pathology — MCQs

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