General Pathology Practice Questions

Q: Alport syndrome is associated with a defect in which type of collagen?

Collagen type IV. **Explanation:** **Alport Syndrome** is a hereditary nephritis caused by mutations in the genes encoding the **Type IV collagen** chains (specifically α3, α4, or α5) [1]. Type IV collagen is a crucial structural component of the **basement membranes**, particularly in the glomeruli, cochlea, and lens of the eye [1]. The defect leads to thinning and splitting of the Glomerular Basement Membrane (GBM), classically described as a **"basket-weave appearance"** on electron microscopy. **Analysis of Options:** * **Option B (Correct):** Type IV collagen is the "Basement Membrane Collagen." Mutations (most commonly X-linked) lead to the clinical triad of progressive hematuria (renal failure), sensorineural hearing loss, and ocular defects (e.g., anterior lenticonus) [1]. * **Option A:** **Type I collagen** is found in bone, skin, and tendons. Defects here lead to **Osteogenesis Imperfecta**. * **Option C:** **Type III collagen** (Reticulin) is found in blood vessels and fetal skin. Defects are associated with the vascular type of **Ehlers-Danlos Syndrome**. * **Option D:** **Type VII collagen** forms anchoring fibrils. Defects lead to **Dystrophic Epidermolysis Bullosa**. **High-Yield Clinical Pearls for NEET-PG:** 1. **Inheritance:** Most common is **X-linked Dominant** (COL4A5 mutation) [1]. 2. **Electron Microscopy (EM):** The gold standard for diagnosis; shows irregular thickening, thinning, and **lamellation** (splitting) of the lamina densa. 3. **Ocular Sign:** **Anterior lenticonus** is pathognomonic for Alport Syndrome. 4. **Goodpasture Syndrome Connection:** Patients with Alport syndrome who receive a kidney transplant may develop anti-GBM antibodies against the "new" Type IV collagen, leading to post-transplant glomerulonephritis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 929-930.

Q: What are hamartomas?

Developmental malformations. **Explanation:** **Hamartomas** are defined as focal, disorganized overgrowths of mature cells and tissues indigenous to the particular site. Although they often form a mass and resemble a neoplasm, they are fundamentally **developmental malformations** rather than true tumors, as they grow at the same rate as the surrounding tissue and lack autonomous growth [1]. * **Why Option B is Correct:** Hamartomas represent an error in organogenesis. A classic example is a **Pulmonary Hamartoma**, which contains disorganized cartilage, connective tissue, and epithelium—all elements normally found in the lung. * **Why Option A is Incorrect:** While some hemangiomas were historically considered hamartomatous, they are now classified as benign neoplasms of blood vessels [1]. * **Why Option C is Incorrect:** A hematoma is simply a localized collection of extravasated blood (a bruise or clot) resulting from trauma or vascular injury, not a developmental growth. * **Why Option D is Incorrect:** An antibioma is a tough, fibrous mass that forms when a brain or soft tissue abscess is treated with antibiotics without adequate surgical drainage. **High-Yield Clinical Pearls for NEET-PG:** * **Cytogenetics:** Many hamartomas show clonal chromosomal aberrations (e.g., 6p21 or 12q14-15), blurring the line between malformation and neoplasia. * **Cowden Syndrome:** Multiple hamartomas (especially of the skin and GI tract) caused by **PTEN** gene mutations. * **Peutz-Jeghers Syndrome:** Characterized by multiple hamartomatous polyps in the GI tract. * **Tuberous Sclerosis:** Associated with cardiac rhabdomyomas and renal angiomyolipomas (both hamartomatous) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 481-482.

Q: What is the marker for Langerhans cells histiocytes?

CD 1a. **Explanation:** Langerhans Cell Histiocytosis (LCH) is a clonal proliferation of Langerhans cells, which are specialized dendritic cells normally found in the skin. [1] **1. Why CD1a is correct:** Langerhans cells are characterized by specific immunophenotypic markers. **CD1a** and **Langerin (CD207)** are the most specific diagnostic markers used in immunohistochemistry to identify these cells. [1] CD1a is a glycoprotein structurally related to MHC molecules and is highly expressed on the surface of Langerhans cells. Additionally, these cells are **S-100 positive** and contain characteristic **Birbeck granules** (tennis-racket shaped organelles) on electron microscopy. [1] **2. Why other options are incorrect:** * **CD20:** This is a classic marker for **B-lymphocytes**. It is used to identify B-cell lymphomas but has no expression in histiocytic disorders. * **CD3:** This is the definitive marker for **T-lymphocytes**. It is part of the T-cell receptor complex and is used to identify T-cell lineages. * **CD30:** Also known as Ki-1 antigen, this is a marker for activated B and T cells. It is the hallmark marker for **Hodgkin Lymphoma** (Reed-Sternberg cells) and **Anaplastic Large Cell Lymphoma (ALCL)**. **High-Yield Clinical Pearls for NEET-PG:** * **Electron Microscopy:** Look for **Birbeck Granules** (Tennis-racket appearance). [1] * **Immunohistochemistry (IHC):** Positive for **CD1a, Langerin (most specific), and S-100**. * **Clinical Presentation:** Can range from a solitary bone lesion (Eosinophilic Granuloma) to multisystem involvement (Letterer-Siwe disease). * **Hand-Schüller-Christian triad:** Bone lesions (calvarium), Exophthalmos, and Diabetes Insipidus. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 629-630.

Question 1

Alport syndrome is associated with a defect in which type of collagen?

Accepted Answer

Collagen type IV

Answer

Collagen type I

Answer

Collagen type III

Answer

Collagen type VII

Question 2

Caseous necrosis is seen in which of the following conditions?

Accepted Answer

Histoplasmosis

Answer

CMV infection

Answer

Pneumococcal infection

Answer

HSV infection

Question 3

Oncocytes are found in all of the following locations except?

Accepted Answer

Pineal gland

Answer

Thyroid

Answer

Pancreas

Answer

Pituitary

Question 4

Coagulative necrosis is typically seen in which of the following conditions?

Accepted Answer

Tuberculosis

Answer

Sarcoidosis

Answer

Cryptococcal infection

Answer

All of the above

Question 5

A 66-year-old woman dies of severe congestive heart failure. Her past medical history is remarkable for rheumatoid arthritis that first manifested at the age of 35. The autopsy revealed splenomegaly, hepatomegaly, and glomerulopathy. The spleen, liver, and kidneys showed a similar waxy texture. Which of the following mechanisms explains these clinical and pathologic findings?

Accepted Answer

Accumulation of amyloid

Answer

Atherosclerosis of coronary arteries

Answer

Coxsackievirus myocarditis

Answer

Mutation of myosin chain genes

Question 6

Increased number of autophagic vacuoles is seen in which of the following cellular adaptations?

Accepted Answer

Atrophy

Answer

Hypertrophy

Answer

Hyperplasia

Answer

Metaplasia

Question 7

What are hamartomas?

Accepted Answer

Developmental malformations

Answer

Hemangiomas

Answer

Hematomas

Answer

Antibiomas

Question 8

Barbiturate ingestion is associated with hypertrophy of which cellular organelle?

Accepted Answer

Endoplasmic reticulum

Answer

Mitochondria

Answer

Golgi apparatus

Answer

Nucleolus

Question 9

What is the marker for Langerhans cells histiocytes?

Accepted Answer

CD 1a

Answer

CD 20

Answer

CD 3

Answer

CD 30

Question 10

In hemochromatosis, which of the following is NOT affected?

Accepted Answer

Central Nervous System (CNS)

Answer

Bronze Pancreas

Answer

Hyperpigmentation

Answer

Restrictive cardiomyopathy

General Pathology — MCQs

General Pathology — MCQs

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