Li–Fraumeni syndrome is associated with mutations in which of the following genes?
All of the following statements about Giant cell arteritis are true except?
What change is seen in the vessels during the initial stage of Raynaud's phenomenon?
Which of the following conditions can lead to pulmonary infarction?
What occurs during the stage of Grey hepatization?
Oncocytic carcinoma arises from -
Lines of Zahn occur in -
What is the term for a localized malformation composed of an excessive but disorganized arrangement of cells and tissues indigenous to the site?
In which organ do atheromatous changes of blood vessels typically occur early in the disease process?
Which of the following best describes the shape of Birbeck granules?
NEET-PG 2012 - Pathology NEET-PG Practice Questions and MCQs
Question 11: Li–Fraumeni syndrome is associated with mutations in which of the following genes?
- A. Gene RB1
- B. Gene BRCA1
- C. Gene P21
- D. Gene TP53 (Correct Answer)
Explanation: ***Gene TP53*** - Li-Fraumeni syndrome is a rare, inherited cancer susceptibility syndrome associated with germline mutations in the **TP53 tumor suppressor gene**. - The **TP53 gene** encodes the p53 protein, which plays a critical role in cell cycle arrest, DNA repair, and initiation of apoptosis in response to cellular stress, thus preventing tumor formation. *Gene P21* - The **p21 gene** (CDKN1A) is a cyclin-dependent kinase inhibitor that acts downstream of p53, mediating p53-induced cell cycle arrest. - While p21 is involved in the p53 pathway, mutations in p21 itself are not the primary cause of Li-Fraumeni syndrome. *Gene RB1* - The **RB1 gene** encodes the retinoblastoma protein, a tumor suppressor involved in cell cycle regulation, particularly in controlling passage from G1 to S phase. - Mutations in **RB1** are primarily associated with hereditary retinoblastoma and osteosarcoma, not Li-Fraumeni syndrome. *Gene BRCA1* - The **BRCA1 gene** is a tumor suppressor gene involved in DNA repair, especially homologous recombination. - Germline mutations in **BRCA1** are strongly associated with hereditary breast and ovarian cancer syndrome, not Li-Fraumeni syndrome.
Question 12: All of the following statements about Giant cell arteritis are true except?
- A. Involves large to small sized arteries (Correct Answer)
- B. Granulomatous inflammation
- C. Segmental nature of the involvement
- D. Can involve the aorta and its major branches
Explanation: ***Involves large to small sized arteries*** - Giant cell arteritis (GCA) predominantly affects **medium to large-sized arteries**, most commonly the branches of the **carotid artery**, such as the temporal arteries [1]. - While it can affect various arteries, it does not typically involve **small-sized arteries**, such as arterioles, directly as a primary site of inflammation. *Granulomatous inflammation* - GCA is characterized histologically by **granulomatous inflammation** within the arterial wall, which includes multinucleated **giant cells** and lymphocytes [2]. - This specific inflammatory pattern is a hallmark feature used in the diagnosis of GCA upon biopsy [2]. *Segmental nature of the involvement* - The arterial inflammation in GCA is often **segmental**, meaning that affected arteries may have inflamed and non-inflamed sections alternating along their length [2]. - This segmental involvement often necessitates **longer biopsies** (e.g., 2-3 cm for temporal artery biopsy) to increase the diagnostic yield. *Can involve the aorta and its major branches* - GCA can indeed affect the **aorta** (aortitis) and its major branches, leading to complications like **aneurysms** or **dissections**. - Involvement of these larger vessels can manifest as symptoms such as **claudication** in the limbs or asymptomatic aneurysms detectable on imaging [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 688-689. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 516-517.
Question 13: What change is seen in the vessels during the initial stage of Raynaud's phenomenon?
- A. No pathological changes (functional vasospasm only) (Correct Answer)
- B. Thrombosis
- C. Fibrinoid necrosis
- D. Hyaline sclerosis
Explanation: ***No pathological changes (functional vasospasm only)*** - Raynaud's phenomenon, particularly **primary Raynaud's** (Raynaud's disease), is characterized by **functional vasospasm** of arterioles, especially in fingers and toes, in response to cold or stress [1]. - In its initial stages, there are no structural changes or pathological alterations within the vessel walls; the vasoconstriction is entirely **functional** [1]. *Thrombosis* - **Thrombosis** involves the formation of a blood clot within a vessel, obstructing blood flow. - While severe Raynaud's can, in rare cases, lead to digital ischemia and microthrombosis, it is **not the primary or initial change** seen in typical Raynaud's phenomenon. *Fibrinoid necrosis* - **Fibrinoid necrosis** is a type of vascular damage associated with severe autoimmune diseases or malignant hypertension, where fibrin and plasma proteins deposit in the vessel wall. - This is a **structural, irreversible change** and is not characteristic of the initial, functional vasospasm seen in Raynaud's phenomenon. *Hyaline sclerosis* - **Hyaline sclerosis** is a change in small arteries and arterioles, often seen in benign essential hypertension or as part of the aging process, where the vessel wall thickens and becomes hyaline (glassy) due to plasma protein leakage and fibrosis. - This represents a **chronic structural change** and is not the acute, intermittent, functional vasoconstriction defining the initial stage of Raynaud's. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 520-522.
Question 14: Which of the following conditions can lead to pulmonary infarction?
- A. Saddle embolus at bifurcation
- B. Arterioles being blocked
- C. None of the above.
- D. Blockage of 2nd and 3rd generation end arteries (Correct Answer)
Explanation: ***None*** - Indicates that all the listed options do indeed contribute to **pulmonary infarction**. - **Pulmonary infarction** typically occurs due to vascular obstruction; thus, this choice signifies all other options are related. [1] *Saddle embolus at bifurcation* - A **saddle embolus** can cause significant blockage at the **pulmonary artery bifurcation**, leading to acute pulmonary infarction. [2] - This type of embolism can severely reduce blood supply to both lungs, directly contributing to infarction. [3] *Arterioles are blocked* - Obstruction of **small arterioles** can lead to localized ischemia and subsequent infarction in the pulmonary region. [1] - This phenomenon is consistent with the pathophysiology of pulmonary infarction, hence it is a contributing factor. *Blockage of 2nd and 3rd gen end arteries* - Infarction can occur if there is blockage of the **2nd and 3rd generation of pulmonary arteries**, leading to compromised blood flow. [1] - These smaller branches play a critical role in perfusing lung tissue, and their blockage can result in pulmonary infarction. [4] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 137-138. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 323-324. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, p. 140. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 705-706.
Question 15: What occurs during the stage of Grey hepatization?
- A. Accumulation of fibrin (Correct Answer)
- B. Red blood cells fill the alveoli
- C. White blood cells fill the alveoli
- D. Bacteria fill the alveoli
Explanation: ***Accumulation of fibrin*** - Grey hepatization is characterized by the **presence of fibrinous exudate** in the alveoli, indicating significant lung pathology, usually in cases of pneumonia [1,2]. - This stage follows red hepatization and reflects the **progression of inflammation** within the lung tissue [1,2]. *RBC's fill the alveoli* - This occurs during the **red hepatization** stage, where RBCs invade alveoli, not grey hepatization [1,2]. - **Grey hepatization** is marked by **fibrinous deposits** instead of erythrocytes [1,2]. *Organisms fill the alveoli* - While organisms, such as bacteria, can be present, they are more characteristic of the **initial infection phase** rather than grey hepatization [1]. - This stage reflects more on the **inflammatory response** than the presence of pathogens. *WBC's fill the alveoli* - The infiltration of **WBCs (like neutrophils)** represents an earlier inflammatory process, usually preceding grey hepatization [1,2]. - In grey hepatization, the focus is on the **accumulation of fibrin**, not directly on WBC infiltration [1,2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 711-712. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 317-318.
Question 16: Oncocytic carcinoma arises from -
- A. Perivascular region
- B. Renal glomerulus
- C. Loop of Henle
- D. Collecting duct (intercalated cells) (Correct Answer)
Explanation: ***Collecting duct*** - Oncocytic carcinoma primarily originates from the **collecting ducts** of the kidney, where oncocytes are characteristically found [1]. - It is associated with specific **morphological features**, including abundant eosinophilic cytoplasm. *Loop of henle* - This part of the nephron primarily functions in **concentration of urine** and is not a common site for oncocytic tumors. - Tumors arising here typically do not exhibit **oncocytic features** and are more often linked to different renal cell types. *Glomerulus* - The glomerulus is involved in **filtration of blood** and lacks oncocytic differentiation. - Oncocytic carcinoma does not arise from glomerular structures, as it features distinct cellular characteristics. *Perivascular* - This term refers to the tissue surrounding blood vessels and is not a site for oncocytic carcinoma development. - Such tumors would not align with the histological features or origins typically seen in oncocytic carcinoma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 959.
Question 17: Lines of Zahn occur in -
- A. Thrombus (Correct Answer)
- B. Embolus
- C. Infarct
- D. Postmortem clot
Explanation: ***Thrombus*** - **Lines of Zahn** are alternating layers of **platelets** (lighter bands) and **red blood cells** (darker bands) that are characteristic of a **thrombus** formed in flowing blood. - Their presence indicates that the clot was formed in a vessel where there was **blood flow** *Infarct* - An **infarct** is an area of **ischemic necrosis** caused by occlusion of either the arterial supply or venous drainage in a particular tissue. - While a thrombus can cause an infarct, an infarct itself does not contain Lines of Zahn; rather, it is the consequence of the thrombus. *Embolus* - An **embolus** is a detached intravascular solid, liquid, or gaseous mass that is carried by the blood to a site distant from its origin. - An embolus can be a fragment of a thrombus and therefore could contain Lines of Zahn, but the primary structure where these lines are formed is the stationary thrombus within a vessel. *Postmortem clot* - A **postmortem clot** forms after death and is typically gelatinous, poorly attached to the vessel wall, and has a dark red dependent portion (due to red cell settling) and a yellowish upper portion (like "chicken fat"). - It does not exhibit the layered architecture of platelets and red blood cells seen in **Lines of Zahn**, as there is no active blood flow or coagulation process at play.
Question 18: What is the term for a localized malformation composed of an excessive but disorganized arrangement of cells and tissues indigenous to the site?
- A. Hamartoma (Correct Answer)
- B. Malignant tumor
- C. Choristoma
- D. None of the options
Explanation: ***Hamartoma*** - A **hamartoma** is an overgrowth of cells and tissues that are normally found in the affected area, but in a disordered fashion, creating a tumor-like growth [1]. - It's a **benign (non-cancerous)** lesion, often congenital, that grows at the same rate as the surrounding tissues. *Malignant tumor* - A **malignant tumor** is characterized by uncontrolled cell growth that invades surrounding tissues and can metastasize to distant sites. - Unlike a hamartoma, a malignant tumor consists of **abnormal, dysplastic cells** that do not resemble the normal tissues of the organ. *Choristoma* - A choristoma is a **benign tumor-like growth** consisting of normal cells or tissues that are **heterotopic**, meaning they are located in an abnormal site. - An example is the presence of pancreatic tissue in the wall of the stomach, which is normal tissue in an abnormal location, unlike a hamartoma which has normal tissue in the correct location but in a disorganized manner. *None of the options* - This option is incorrect because **hamartoma** accurately describes the overgrowth of a skin structure at a localized region made of normal, but disorganized, tissue [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Disorders Involving Inflammatory And Haemopoietic Cells, pp. 651-652.
Question 19: In which organ do atheromatous changes of blood vessels typically occur early in the disease process?
- A. Kidney
- B. Heart (Correct Answer)
- C. Liver
- D. Spleen
Explanation: ***Heart*** - The **coronary arteries**, which supply the heart, are particularly susceptible to **atherosclerosis** due to high blood flow turbulence and shear stress [1]. - Early atheromatous changes often begin in these arteries, leading to conditions like **coronary artery disease (CAD)** [1]. *Kidney* - While the kidneys can be affected by **atherosclerosis** (renal artery stenosis), it typically occurs later in the disease process or in the presence of more widespread disease [1]. - The primary early site for systemic atherosclerosis is generally not the renal arteries. *Liver* - The liver is not a primary site for the development of **atherosclerosis** within its own blood vessels. - Liver disease can influence lipid metabolism, but directly developing atheroma within hepatic arteries is uncommon. *Spleen* - The spleen is rarely the primary or early site for **atheromatous changes**. - Its blood vessels are generally less prone to the turbulent flow and plaque formation seen in major arteries. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 499-508.
Question 20: Which of the following best describes the shape of Birbeck granules?
- A. Resembling a tennis racket (Correct Answer)
- B. Resembling a hockey stick
- C. Resembling a bat
- D. Resembling a ball
Explanation: ***Tennis racket*** [1] - Birbeck granules are distinctive for their **tennis racket shape**, consisting of an elongated area and a bulbous end [1]. - They are typically found in **Langerhans cell histiocytosis** and are associated with **CD1a+** staining [1]. *Bat* - The term "bat" does not accurately describe the structure or morphology of Birbeck granules. - Unlike bats, Birbeck granules have a **specific elongated shape** with a bulbous tip rather than bat wings. *Hockey stick* - This shape implies a straight handle and a flat blade, which does not represent the **widely tapered ends** of Birbeck granules. - The **characteristic morphology** does not align with any hockey stick features. *Ball* - The term "ball" indicates a spherical shape, which is not fitting for Birbeck granules, as they are **elongated** and striated. - Birbeck granules are defined specifically by their **tapered structure**, contrasting markedly with a circular form. **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, p. 630.