Respiratory Pathology Practice Questions

Q: A 65-year-old smoker presents with chronic cough, hemoptysis, and weight loss. Chest X-ray shows a cavitary lesion. What is the most likely diagnosis?

Squamous cell carcinoma. **Explanation:** The clinical presentation of a chronic smoker with a **cavitary lesion** on imaging is a classic "high-yield" scenario for **Squamous Cell Carcinoma (SCC)** of the lung. [1] **Why Squamous Cell Carcinoma is correct:** SCC is strongly associated with smoking and typically arises **centrally** in the bronchi [1], [2]. The hallmark of SCC is its tendency to undergo **central necrosis**, leading to the formation of a **cavity** [1], [2]. Histologically, it is characterized by keratin pearls and intercellular bridges [1], [2]. **Analysis of Incorrect Options:** * **A. Undifferentiated Large Cell Carcinoma:** While it can occasionally cavitate, it is a diagnosis of exclusion and is less common than SCC. It typically presents as a large peripheral mass. * **B. Small Cell Carcinoma:** This is a central tumor strongly linked to smoking, but it is characterized by rapid growth and early metastasis. It is notorious for **not cavitating**. * **C. Adenocarcinoma:** This is the most common lung cancer overall and the most common in non-smokers. It typically presents as a **peripheral lesion** and rarely shows cavitation [1]. **NEET-PG High-Yield Pearls:** * **Mnemonic for SCC:** Remember the **4 C’s**: **C**entral, **C**igarettes, **C**avitation, and **C**alcium (due to PTHrP-induced hypercalcemia). * **Location:** SCC and Small Cell are usually **Central**; Adenocarcinoma and Large Cell are usually **Peripheral** [1]. * **Paraneoplastic Syndromes:** SCC is associated with Hypercalcemia (PTHrP), whereas Small Cell is associated with SIADH, ACTH (Cushing’s), and Lambert-Eaton Syndrome. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 723-724.

Q: Examination of the lungs of a 55-year-old coal miner during autopsy reveals small hilar lymph nodes which are jet black in colour. The microscopic appearance of one lymph node is shown. What is the most likely diagnosis?

Anthracotic pigmentation. ***Anthracotic pigmentation*** - **Coal dust inhalation** in miners leads to deposition of **carbon particles** in hilar lymph nodes, causing the characteristic **jet black coloration**. - Microscopy shows **anthracotic pigment** (carbon particles) within **macrophages** without significant inflammation or fibrosis in early stages. *Metastasis* - Metastatic deposits typically appear as **gray-white nodules** rather than jet black pigmentation. - Microscopy would show **malignant cells** with cellular atypia, not carbon-laden macrophages. *Hemosiderosis* - Results from **iron deposition** causing **golden-brown pigmentation**, not jet black coloration. - Microscopy reveals **hemosiderin-laden macrophages** that stain positive with **Prussian blue stain** for iron. *Sarcoidosis* - Characterized by **non-caseating granulomas** with **epithelioid cells** and **giant cells**. - Lymph nodes appear **enlarged and firm** but typically **gray-pink**, not jet black in color.

Q: A patient underwent lung transplantation. Below is the gross appearance of the post-mortem lung. What is the most likely diagnosis?

Miliary tuberculosis. ***Miliary tuberculosis*** - In **immunocompromised patients** (lung transplant recipients), tuberculosis can disseminate and present as **millet-seed sized nodules** scattered throughout both lungs on gross examination. - The **post-mortem lung** appearance with multiple small, uniform nodules is classic for **miliary TB**, especially in the setting of immunosuppression following transplantation. *Bronchiectasis* - Characterized by **abnormally dilated and thickened airways** with a "tram-track" appearance on imaging, not multiple small nodules. - Gross examination would show **cystic dilatation of bronchi** and bronchioles, often filled with purulent secretions. *Lung abscess* - Presents as a **single or few large cavitary lesions** filled with pus, not multiple small nodules. - Gross appearance would show **thick-walled cavities** with necrotic centers, typically larger than millet seeds. *Lung carcinoma* - Typically appears as **discrete mass lesions** or **irregular nodules** of varying sizes, not uniform small nodules. - Gross examination would reveal **heterogeneous tissue** with possible necrosis, hemorrhage, or calcification, distinct from the uniform miliary pattern.

Q: What is the characteristic feature of Kartagener's syndrome?

Ultrastructural abnormality of cilia. **Explanation:** Kartagener’s syndrome is a subset of **Primary Ciliary Dyskinesia (PCD)**, an autosomal recessive disorder. The hallmark of this condition is not the absence of cilia, but rather their **dysfunction** due to structural defects. **1. Why Option C is Correct:** The core pathology lies in the **ultrastructural abnormality** of the cilia. Under electron microscopy, the most common finding is the **absence or deficiency of outer and/or inner dynein arms**. Dynein arms are protein complexes containing ATPase, which provide the energy required for ciliary movement. Other abnormalities can include defects in the radial spokes or the central microtubule pair (9+2 arrangement). Because the structure is flawed, the cilia are either immotile or show ineffective, dyssynchronous beating. **2. Why Other Options are Incorrect:** * **Option A & B:** In Kartagener’s syndrome, cilia are present and fully developed in terms of number and length. The defect is internal (molecular/structural), not a failure of ciliogenesis or growth. **3. Clinical Pearls for NEET-PG:** * **The Classic Triad:** Kartagener’s syndrome is characterized by: 1. **Situs Inversus** (transposition of viscera). 2. **Bronchiectasis** (due to poor mucus clearance). 3. **Chronic Sinusitis** (leading to nasal polyps). * **Infertility:** Males are often infertile due to immotile spermatozoa (which share similar flagellar ultrastructure), while females may have reduced fertility due to affected cilia in the fallopian tubes. * **Diagnostic Gold Standard:** Electron microscopy of a biopsy (usually from the nasal mucosa or bronchus) to visualize the dynein arm defect. * **Screening Test:** Saccharin test (shows prolonged transit time) or exhaled Nitric Oxide (characteristically low in PCD).

Q: Asbestosis is associated with all of the following except:

Central emphysema. **Explanation:** **Asbestosis** is a chronic fibrotic lung disease caused by the inhalation of asbestos fibers. The correct answer is **Central emphysema** because emphysema is a component of Chronic Obstructive Pulmonary Disease (COPD), primarily associated with **smoking** and **alpha-1 antitrypsin deficiency**, rather than asbestos exposure. **Analysis of Options:** * **A. Central emphysema (Correct):** Asbestosis is a **Restrictive Lung Disease**, characterized by stiffening of the lung parenchyma. Emphysema, an **Obstructive** pathology involving alveolar wall destruction, is not a direct pathological feature of asbestosis. * **B. Interstitial fibrosis:** This is the hallmark of asbestosis. Inhaled fibers deposit in the distal airways and alveoli, triggering macrophage activation and subsequent diffuse interstitial fibrosis, typically starting in the **lower lobes**. * **C. Pleural effusion:** Asbestos exposure is notorious for affecting the pleura. It can cause benign asbestos pleural effusion (BAPE), pleural plaques (most common sign), and pleural thickening. * **D. Carcinoma of the larynx:** While lung cancer and mesothelioma are most common, asbestos is also a recognized risk factor for extra-pulmonary malignancies, including cancers of the **larynx**, esophagus, and gastrointestinal tract. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic Finding:** **Asbestos bodies** (Ferruginous bodies) – golden-brown, fusiform/beaded rods coated with iron. * **Radiology:** Characterized by "Ground glass" appearance and subpleural curvilinear lines. **Pleural plaques** (calcified) on the diaphragm are highly suggestive. * **Cancer Risk:** The most common cancer in asbestos workers is **Bronchogenic Carcinoma**, but the most specific is **Mesothelioma**. * **Synergy:** Smoking and asbestos exposure have a **multiplicative (synergistic) effect** on the risk of bronchogenic carcinoma.

Question 1

Extensive pleural thickening and calcification, especially involving the diaphragmatic pleura, are classical features of which condition?

Accepted Answer

Asbestosis

Answer

Coal worker's pneumoconiosis

Answer

Silicosis

Answer

Siderosis

Question 2

Intralobar sequestration of the lung is commonest in which segment?

Accepted Answer

Posterior basal segment of the lower lobe

Answer

Apical segment of the upper lobe

Answer

Medial segment of the middle lobe

Answer

Lateral basal segment of the lower lobe

Question 3

A 65-year-old smoker presents with chronic cough, hemoptysis, and weight loss. Chest X-ray shows a cavitary lesion. What is the most likely diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Undifferentiated large cell carcinoma

Answer

Small cell carcinoma

Answer

Adeno carcinoma

Question 4

Examination of the lungs of a 55-year-old coal miner during autopsy reveals small hilar lymph nodes which are jet black in colour. The microscopic appearance of one lymph node is shown. What is the most likely diagnosis?

Accepted Answer

Anthracotic pigmentation

Answer

Metastasis

Answer

Hemosiderosis

Answer

Sarcoidosis

Question 5

Periodic Acid Schiff (PAS) stain positive intra-alveolar material is seen in which of the following conditions?

Accepted Answer

Pulmonary Alveolar Proteinosis

Answer

Alpha 1 antitrypsin deficiency

Answer

Lipoid pneumonia

Answer

Abetalipoproteinemia

Question 6

A patient underwent lung transplantation. Below is the gross appearance of the post-mortem lung. What is the most likely diagnosis?

Accepted Answer

Miliary tuberculosis

Answer

Bronchiectasis

Answer

Lung abscess

Answer

Lung carcinoma

Question 7

What is the characteristic feature of Kartagener's syndrome?

Accepted Answer

Ultrastructural abnormality of cilia

Answer

Absence of cilia

Answer

Undeveloped cilia

Answer

None of the above

Question 8

Asbestosis is associated with all of the following except:

Accepted Answer

Central emphysema

Answer

Interstitial fibrosis

Answer

Pleural effusion

Answer

Carcinoma of the larynx

Question 9

Which condition is characterized by alveolar hemorrhage and hemosiderin-laden macrophages?

Accepted Answer

Goodpasture syndrome

Answer

Sarcoidosis

Answer

Bronchial pneumonia

Answer

Bronchiectasis

Question 10

Which of the following is a finding in biopsy of mesothelioma of pleura?

Accepted Answer

Intense fibrosis

Answer

Myelin figures

Answer

Desmosomes

Answer

Weibel-Palade bodies

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?