Respiratory Pathology Practice Questions

Q: S1ADH is associated with which of the following malignancies?

Small cell carcinoma of the lung. **Explanation:** **Small cell carcinoma (SCC) of the lung** is the correct answer because it is a neuroendocrine tumor derived from Kulchitsky cells (APUD cells). These cells have the metabolic machinery to synthesize and secrete ectopic hormones [1]. **SIADH (Syndrome of Inappropriate Antidiuretic Hormone)** is a classic paraneoplastic syndrome associated with SCC, where the tumor secretes ectopic ADH, leading to hyponatremia and concentrated urine [1]. **Analysis of Incorrect Options:** * **Adenocarcinoma:** This is the most common lung cancer in non-smokers and females. It is typically peripheral and is more commonly associated with **hypertrophic osteoarthropathy (digital clubbing)** rather than endocrine syndromes. * **Squamous Cell Carcinoma:** This is strongly associated with smoking and a central location. Its classic paraneoplastic manifestation is **Hypercalcemia** due to the secretion of Parathyroid Hormone-related Protein (PTHrP). (Mnemonic: **S**quamous = **S**tony calcium). * **Mixed Cell Tumor:** These are rare and do not have a specific, high-yield association with SIADH compared to the classic neuroendocrine profile of Small Cell Carcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Small Cell Carcinoma Associations:** SIADH, ACTH secretion (Cushing Syndrome), and Lambert-Eaton Myasthenic Syndrome [1]. * **Histology of SCC:** Look for "Oat cell" appearance, scant cytoplasm, nuclear molding [2], and the **Azzopardi effect** (DNA staining of vessel walls). * **Treatment Note:** SCC is usually disseminated at the time of diagnosis [1]; therefore, it is treated primarily with chemotherapy/radiotherapy rather than surgery [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 725-727. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 337-338.

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.

Question 1

S1ADH is associated with which of the following malignancies?

Accepted Answer

Small cell carcinoma of the lung

Answer

Adenocarcinoma of the lung

Answer

Squamous cell carcinoma of the lung

Answer

Mixed cell tumor of the lung

Question 2

All of the following features are seen in asbestosis except?

Accepted Answer

Emphysema

Answer

Diffuse pulmonary interstitial fibrosis

Answer

Fibrous pleural thickening

Answer

Calcific pleural plaques

Question 3

What type of lung carcinoma is characterized by the presence of hyperscretory granules?

Accepted Answer

Small cell carcinoma

Answer

Adenocarcinoma

Answer

Large cell carcinoma

Answer

Bronchoalveolar carcinoma

Question 4

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 5

Increased Reid Index is used to characterize which condition?

Accepted Answer

Chronic Bronchitis

Answer

Bronchiectasis

Answer

Bronchial Asthma

Answer

Emphysema

Question 6

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 7

Necrotic nodules in the lung are seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Tuberculosis

Answer

Sarcoidosis

Answer

Rheumatoid Arthritis

Question 8

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 9

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 10

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

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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