General Pathology Practice Questions

Q: Turner's Syndrome is associated with?

45 chromosomes. **Explanation:** **Turner’s Syndrome (45, XO)** is a genetic disorder caused by complete or partial monosomy of the X chromosome. It is the most common sex chromosome abnormality in females. 1. **Why Option A is Correct:** The hallmark of Turner’s Syndrome is the absence of one X chromosome, resulting in a total of **45 chromosomes (45, XO)**. This occurs due to non-disjunction during meiosis (most commonly paternal) [1]. 2. **Why Other Options are Incorrect:** * **Option B (Presence of Barr bodies):** A Barr body is an inactivated X chromosome. According to the Lyon hypothesis, the number of Barr bodies is equal to (Total X chromosomes - 1). Since Turner’s patients have only one X chromosome (1 - 1 = 0), they are **Barr body negative**. * **Option C (Low FSH levels):** Turner’s Syndrome is characterized by **"streak ovaries"** (gonadal dysgenesis). The lack of estrogen leads to a loss of negative feedback on the pituitary, resulting in **elevated** levels of Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). This is a classic example of **hypergonadotropic hypogonadism**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of primary amenorrhea.** * **Clinical Features:** Short stature (due to *SHOX* gene deletion), webbed neck (cystic hygroma), widely spaced nipples (shield chest), and cubitus valgus [1]. * **Cardiac Associations:** Bicuspid aortic valve (most common) and Coarctation of the aorta. * **Renal Association:** Horseshoe kidney. * **Genetics:** 50% are 45,XO; others are mosaics (e.g., 45,XO/46,XX) or have structural abnormalities (isochromosome Xq) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-177.

Q: The odontogenic neoplasm, which is microscopically composed of loose, primitive-appearing connective tissue that resembles dental pulp, is known as _____.

Odontogenic myxoma. **Explanation:** The correct answer is **Odontogenic Myxoma**. This neoplasm is derived from the odontogenic ectomesenchyme (specifically the dental papilla, follicle, or periodontal ligament) [1]. **Why Odontogenic Myxoma is correct:** Microscopically, it is characterized by a **hypocellular** arrangement of stellate or spindle-shaped cells embedded in an abundant **mucoid/myxomatous extracellular matrix**. This appearance closely mimics the **primitive connective tissue of the dental pulp**. On imaging, it typically presents as a multilocular radiolucency with a characteristic **"soap bubble"** or **"honeycomb"** appearance, often showing "string-of-tennis-racket" bony trabeculations. **Why the other options are incorrect:** * **Odontoma:** These are hamartomas rather than true neoplasms [1]. They consist of mature enamel, dentin, cementum, and pulp tissue arranged either in a tooth-like shape (Compound) or a disorganized mass (Complex). * **Ameloblastoma:** This is an epithelial tumor, not mesenchymal [1]. It is characterized by islands of odontogenic epithelium with peripheral palisading cells (reverse polarity) and a central area resembling stellate reticulum. * **Ameloblastic Fibroma:** This is a mixed tumor (epithelial and mesenchymal). While it contains primitive-looking connective tissue, it must also feature islands and cords of odontogenic epithelium to satisfy the diagnosis. **NEET-PG High-Yield Pearls:** * **Histology Keyword:** "Stellate cells in a loose myxoid stroma." * **Radiology Keyword:** "Soap bubble" or "Tennis racket" appearance. * **Consistency:** Grossly, the tumor has a gelatinous or slimy consistency, making complete surgical removal difficult (high recurrence rate). * **Origin:** Derived from the **mesenchymal** component of the tooth germ [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 741-742.

Q: Platelet activating factor causes all of the following except:

Bronchodilation. **Explanation:** Platelet Activating Factor (PAF) is a potent phospholipid-derived mediator produced by various cells, including platelets, mast cells, neutrophils, and endothelial cells, via the action of phospholipase A2. **Why Bronchodilation is the correct answer:** PAF is a powerful **bronchoconstrictor**. It is approximately 100 to 1,000 times more potent than histamine in inducing bronchospasm. Therefore, it causes broncho-constriction, not dilation. This makes it a key mediator in the pathogenesis of asthma and anaphylactic reactions. **Analysis of incorrect options:** * **Vasoconstriction:** At high concentrations, PAF causes systemic vasoconstriction. However, it is unique because, at very low concentrations, it can cause vasodilation and increased vascular permeability (more potent than histamine). * **Platelet Aggregation:** As the name suggests, PAF’s primary function is to induce platelet aggregation and the subsequent release of platelet granules (degranulation). * **Signal Transmission:** PAF acts as a crucial signaling molecule. It binds to G-protein-coupled receptors (GPCRs) to trigger intracellular signaling pathways, facilitating communication between inflammatory cells and the endothelium. **High-Yield Clinical Pearls for NEET-PG:** * **Source:** Derived from membrane phospholipids by Phospholipase A2. * **Vascular Effects:** Causes wheal and flare reactions; it is a potent inducer of **increased vascular permeability** (leading to edema). * **Chemotaxis:** PAF is a strong chemoattractant for neutrophils and eosinophils. * **Leukocyte Activation:** It enhances leukocyte adhesion to endothelium, degranulation, and the oxidative burst.

Q: A Barr body is absent in which of the following conditions?

Turner syndrome. ### Explanation **1. Understanding Barr Bodies (The Lyon Hypothesis)** A Barr body is an inactivated X chromosome found in the somatic cells of females [1]. According to the Lyon hypothesis, in individuals with more than one X chromosome, all X chromosomes except one are inactivated to ensure dosage compensation. The number of Barr bodies is calculated using the formula: **Number of Barr bodies = (Total number of X chromosomes – 1).** **2. Why Turner Syndrome is the Correct Answer** * **Turner Syndrome (45, XO):** These individuals have only one X chromosome [1]. Applying the formula (1 – 1 = 0), they have **zero Barr bodies**. Since a Barr body represents an inactivated "extra" X chromosome, its absence is a hallmark of this condition. **3. Analysis of Incorrect Options** * **Klinefelter Syndrome (47, XXY):** Although phenotypically male, these individuals possess two X chromosomes [1]. One X chromosome undergoes inactivation, resulting in **one Barr body** (2 – 1 = 1). * **Super Female Syndrome (47, XXX):** These individuals have three X chromosomes. Two X chromosomes are inactivated, resulting in **two Barr bodies** (3 – 1 = 2). **4. NEET-PG High-Yield Clinical Pearls** * **Specimen Collection:** Barr bodies are most commonly demonstrated in **buccal mucosal smears** or "drumsticks" in polymorphonuclear leukocytes (neutrophils). * **Lyonization:** This process occurs early in embryonic life (around the blastocyst stage) and is random, fixed, and incomplete (some genes on the inactive X remain active) [1]. * **Rule of Thumb:** If the question asks for the number of Barr bodies, simply subtract 1 from the total number of X chromosomes present in the karyotype. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 173-175.

Question 1

Which of the following statements is NOT true concerning amyloidosis?

Accepted Answer

Amyloidosis of the spleen is associated with severe anemia.

Answer

Amyloidosis associated with multiple myeloma has the poorest prognosis.

Answer

Fine-needle biopsy of subcutaneous abdominal fat is a simple and reliable method for diagnosing secondary systemic amyloidosis.

Answer

Hepatic amyloid disease produces hepatomegaly but rarely jaundice.

Question 2

The dominant histologic feature of infarction is:

Accepted Answer

Coagulative necrosis

Answer

Liquefactive necrosis

Answer

Chronic inflammation

Answer

Scar tissue

Question 3

Turner's Syndrome is associated with?

Accepted Answer

45 chromosomes

Answer

Presence of Barr bodies

Answer

Low FSH levels

Answer

All of the above

Question 4

The odontogenic neoplasm, which is microscopically composed of loose, primitive-appearing connective tissue that resembles dental pulp, is known as _____.

Accepted Answer

Odontogenic myxoma

Answer

Odontoma

Answer

Ameloblastoma

Answer

Ameloblastic fibroma

Question 5

Which marker is used to assess monoclonality in T-cells?

Accepted Answer

TCR gene rearrangement

Answer

Kappa and Lambda chain

Answer

CD

Answer

CD34

Question 6

Which of the following proteins is known as the "guardian of the genome"?

Accepted Answer

p53

Answer

Mdm2

Answer

p14

Answer

ATM

Question 7

Platelet activating factor causes all of the following except:

Accepted Answer

Bronchodilation

Answer

Vasoconstriction

Answer

Platelet aggregation

Answer

Signal transmission between cells

Question 8

Dystrophic calcification means:

Accepted Answer

Calcification in destroyed tissue with normal calcium level in blood

Answer

Calcium deposits

Answer

Calcification in normal tissue seen in hyperparathyroidism

Answer

Calcification in destroyed tissues with hypercalcemia

Question 9

A Barr body is absent in which of the following conditions?

Accepted Answer

Turner syndrome

Answer

Klinefelter syndrome

Answer

Super female syndrome (Triple X syndrome)

Answer

None of the above

Question 10

Which enzyme converts hydrogen peroxide to water and oxygen?

Accepted Answer

Catalase

Answer

Superoxide dismutase

Answer

Glutathione peroxidase

Answer

Myeloperoxidase

General Pathology — MCQs

General Pathology — MCQs

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