General Pathology Practice Questions

Q: Psammoma bodies are typically seen in which of the following conditions?

Follicular carcinoma of the thyroid. **Explanation** Psammoma bodies are round, microscopic calcifications with a concentric "laminated" or "onion-skin" appearance. They represent a process of dystrophic calcification occurring in necrotic tumor cells. **Why the Correct Answer is Right:** Wait—there is a critical correction needed based on standard pathology: **Psammoma bodies are NOT typically seen in Follicular Carcinoma of the Thyroid.** In fact, the absence of Psammoma bodies is a distinguishing feature of Follicular Carcinoma. They are most classically associated with **Papillary Carcinoma of the Thyroid**. *Note: If the question provided identifies Option A as correct, it is likely a "negative" question or a common distractor error in mock banks. In standard medical literature, Psammoma bodies are the hallmark of Papillary, not Follicular, carcinoma.* **Analysis of Options:** * **Papillary Carcinoma of the Thyroid (Option B):** The most common site for Psammoma bodies in the endocrine system. They are found in the cores of the papillae. * **Serous Cystadenocarcinoma of the Ovary (Option C):** Psammoma bodies are a classic finding in serous tumors of the ovary and are used to differentiate them from mucinous tumors. * **Meningioma (Option D):** These are frequently seen in the psammomatous variant of meningiomas. **High-Yield Clinical Pearls (Mnemonic: PSaMMoma):** To remember the conditions associated with Psammoma bodies, use the mnemonic **PSaMMoma**: 1. **P** - **P**apillary carcinoma of thyroid 2. **S** - **S**erous cystadenocarcinoma of ovary 3. **M** - **M**esothelioma 4. **M** - **M**eningioma **NEET-PG Key Fact:** If you see "Orphan Annie eye nuclei" and "Psammoma bodies" in a thyroid case, the diagnosis is always **Papillary Carcinoma**. Follicular carcinoma is characterized by capsular or vascular invasion, not Psammoma bodies.

Q: The Feulgen reaction is used to test for which of the following?

DNA. **Explanation:** The **Feulgen reaction** is a specialized histochemical staining technique used specifically for the identification and quantification of **DNA** (Deoxyribonucleic acid) within cells. **Why DNA is the correct answer:** The reaction relies on the **acid hydrolysis** of DNA using hydrochloric acid (HCl). This process removes purine bases (adenine and guanine) from the deoxyribose sugar, creating free aldehyde groups (forming apurinic acid). These aldehydes then react with **Schiff’s reagent**, resulting in a characteristic **magenta or reddish-purple** color. Because the reaction is stoichiometric (the intensity of the color is proportional to the amount of DNA), it is frequently used in flow cytometry and image analysis to measure ploidy. **Why other options are incorrect:** * **mRNA, tRNA, and rRNA (Options A, B, D):** These are forms of RNA. The Feulgen reaction is **negative for RNA** because the presence of a hydroxyl group (-OH) at the 2' position of the ribose sugar prevents the acid hydrolysis required to expose aldehyde groups. Therefore, the nucleolus (rich in rRNA) and the cytoplasm (rich in mRNA/tRNA) do not stain with Feulgen. **High-Yield Clinical Pearls for NEET-PG:** * **Specific Stain:** Feulgen is considered the most specific histochemical stain for DNA. * **Counterstain:** Fast Green is commonly used as a counterstain to provide contrast against the magenta DNA. * **RNA Stain:** To differentiate between DNA and RNA, the **Methyl Green-Pyronin (MGP) stain** is used (DNA stains green/blue-green, while RNA stains red/pink). * **Hydrolysis Step:** The critical step in the Feulgen reaction is the controlled acid hydrolysis; over-hydrolysis can lead to a false-negative result by destroying the DNA structure.

Q: Under which of the following conditions does the uterus show both hypertrophy and hyperplasia simultaneously?

Pregnancy. **Explanation:** The correct answer is **Pregnancy**. During pregnancy, the uterus undergoes a massive increase in size and weight (from ~70g to ~1100g) to accommodate the growing fetus. This enlargement is driven by two distinct cellular processes: 1. **Hypertrophy:** An increase in the size of individual myometrial cells (fibers). This is the dominant process, especially after the first trimester, driven by mechanical stretch. 2. **Hyperplasia:** An increase in the total number of myometrial cells. This occurs primarily in the early stages of pregnancy under the influence of estrogen. **Why other options are incorrect:** * **Multiparity:** This refers to a woman who has given birth multiple times. While the uterus may remain slightly larger than a nulliparous uterus (permanent structural changes), active hypertrophy and hyperplasia are features of the *gestational state*, not the state of having previously given birth. * **Nulliparity:** This refers to a woman who has never given birth. The uterus remains in its baseline, non-pregnant state. * **Puberty:** While the uterus grows during puberty due to hormonal stimulation (estrogen), the simultaneous, massive, and rapid combination of both hypertrophy and hyperplasia is the hallmark physiological response unique to **pregnancy**. **High-Yield Clinical Pearls for NEET-PG:** * **Hormonal Influence:** Early uterine growth is due to **Estrogen** (hormone-dependent); later growth is due to **Mechanical Stretch** (pressure-dependent). * **Muscle Arrangement:** The myometrium develops an "interlacing figure-of-eight" pattern, which acts as "living ligatures" to prevent postpartum hemorrhage. * **Uterine Blood Flow:** Increases from 50 mL/min in the non-pregnant state to approximately **500–750 mL/min** at term.

Q: Tuberculosis infection is caused by the deletion of which of the following genes?

ATG5. **Explanation:** The correct answer is **ATG5**. **1. Why ATG5 is correct:** The **ATG5 (Autophagy-related 5)** gene is a critical component of the **autophagy** pathway. Autophagy is a cellular defense mechanism where the host cell (macrophage) sequesters intracellular pathogens like *Mycobacterium tuberculosis* (Mtb) into autophagosomes for degradation. * **Mechanism:** ATG5 is essential for the formation of the autophagosomal membrane. * **Clinical Significance:** Research has shown that the deletion or deficiency of ATG5 in macrophages leads to an inability to control Mtb replication, resulting in severe inflammation, high bacterial load, and increased susceptibility to tuberculosis. This highlights autophagy as a key innate immune response against Mtb. **2. Why the other options are incorrect:** * **BCL-2:** This is an **anti-apoptotic** gene. While it regulates programmed cell death, its primary clinical association is with follicular lymphoma (t14;18 translocation), not the direct susceptibility to TB infection. * **PTEN:** A tumor suppressor gene that inhibits the PI3K/AKT/mTOR pathway. Deletion is associated with various cancers (e.g., Cowden syndrome) rather than TB infection. * **P-53:** Known as the "Guardian of the Genome," it is a tumor suppressor gene involved in DNA repair and apoptosis. Mutations are linked to Li-Fraumeni syndrome and most human cancers. **High-Yield Clinical Pearls for NEET-PG:** * **Autophagy & TB:** *Mycobacterium tuberculosis* survives by inhibiting phagosome-lysosome fusion. Autophagy (driven by ATG5) can bypass this block to kill the bacteria. * **Vitamin D Link:** Vitamin D stimulates the expression of **Cathelicidin**, which further induces autophagy to fight TB. * **IFN-gamma:** This cytokine activates macrophages to induce autophagy, reinforcing the link between cell-mediated immunity and the ATG gene family.

Q: What fixative is used for bone histopathology?

10% formalin. **Explanation:** The primary goal of fixation in histopathology is to preserve biological tissues from decay (autolysis and putrefaction) while maintaining the structural integrity of cells and extracellular matrix. **Why 10% Formalin is Correct:** 10% Neutral Buffered Formalin (NBF) is the standard "universal fixative" used for most tissues, including bone. It works by forming cross-links between proteins (specifically methylene bridges), which stabilizes the tissue architecture. For bone histopathology, fixation in formalin is a mandatory first step before the specimen undergoes **decalcification** (the removal of calcium salts using acids like EDTA or Nitric acid) to allow for thin sectioning [1]. **Why Incorrect Options are Wrong:** * **Normal Saline:** This is an isotonic solution, not a fixative. It is used for temporary transport of fresh tissue (e.g., for immunofluorescence or frozen sections) but does not prevent autolysis. * **Rectified Spirit (Alcohol):** While alcohol is a fixative, it causes significant tissue shrinkage and hardening. It is primarily used for cytology smears or as a secondary fixative, but not as the primary choice for bone. * **Nothing:** Leaving tissue "dry" leads to rapid enzymatic degradation (autolysis) and bacterial growth, rendering the sample non-diagnostic. **High-Yield Clinical Pearls for NEET-PG:** * **Fixative of choice for Electron Microscopy:** Glutaraldehyde. * **Fixative for Testicular Biopsy:** Bouin’s solution (preserves nuclear detail). * **Fixative for Lipids/Fats:** Osmium tetroxide (also used in EM). * **Decalcifying agent of choice:** EDTA (chelating agent) is preferred for preserving enzyme morphology, though 5-10% Nitric acid is faster. * **Ideal ratio:** The volume of fixative should be **10 to 20 times** the volume of the tissue specimen.

Question 1

Psammoma bodies are typically seen in which of the following conditions?

Accepted Answer

Follicular carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Serous cystadenocarcinoma of the ovary

Answer

Meningioma

Question 2

The Feulgen reaction is used to test for which of the following?

Accepted Answer

DNA

Answer

mRNA

Answer

tRNA

Answer

rRNA

Question 3

Under which of the following conditions does the uterus show both hypertrophy and hyperplasia simultaneously?

Accepted Answer

Pregnancy

Answer

Multiparity

Answer

Nulliparity

Answer

Puberty

Question 4

Tuberculosis infection is caused by the deletion of which of the following genes?

Accepted Answer

ATG5

Answer

BCL-2

Answer

PTEN

Answer

P-53

Question 5

Metastatic calcification of the gastrointestinal tract commonly affects the mucosa of:

Accepted Answer

Stomach

Answer

Esophagus

Answer

Ileum

Answer

Rectum

Question 6

During lactation, what change do uterine smooth muscles undergo?

Accepted Answer

Involution

Answer

Hyperplasia

Answer

Hypertrophy

Answer

Atrophy

Question 7

What fixative is used for bone histopathology?

Accepted Answer

10% formalin

Answer

Normal saline

Answer

Rectified spirit

Answer

Nothing

Question 8

Which organ is least resistant to oxygen depletion?

Accepted Answer

Heart

Answer

Liver

Answer

Kidney

Answer

Spleen

Question 9

Which stain is used for tissue fats?

Accepted Answer

Sudan IV

Answer

PAS

Answer

Prussian blue

Answer

Alcian blue

Question 10

A 25-year-old woman died shortly after childbirth. Autopsy revealed the presence of hair, fat, and epithelial cells within the pulmonary vessels. What is the probable cause of death?

Accepted Answer

Amniotic fluid embolism

Answer

Fat embolism

Answer

Disseminated intravascular coagulation (DIC)

Answer

Pulmonary thromboembolism

General Pathology — MCQs

General Pathology — MCQs

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