Respiratory Pathology Practice Questions

Q: Reactivation tuberculosis and primary squamous cell carcinoma of the lung are similar in that they both are commonly associated with:

Cavitation. **Explanation:** The correct answer is **A. Cavitation**. **Why Cavitation?** Cavitation is a hallmark feature shared by both reactivation (secondary) tuberculosis and squamous cell carcinoma (SCC) of the lung. [1] * **Reactivation TB:** Typically involves the lung apices. The hypersensitivity response leads to extensive caseous necrosis, which liquefies and drains into the bronchi, leaving behind a **thick-walled cavity**. * **Squamous Cell Carcinoma:** This tumor is characteristically **central/hilar** in location. Due to its rapid growth, the central portion of the tumor often outstrips its blood supply, leading to **central ischemic necrosis** and subsequent cavitation. [1] **Analysis of Incorrect Options:** * **B. Scar Carcinoma:** Historically associated with Adenocarcinoma (occurring at the site of old scars/infarcts), though this link is now debated. It is not a feature of TB. * **C. Silicosis:** While silicosis significantly increases the risk of developing Tuberculosis (Silicotuberculosis), it is not a common feature of Squamous Cell Carcinoma. * **D. Ectopic Parathormone-like Peptide (PTHrP):** This is a classic paraneoplastic syndrome specifically associated with **Squamous Cell Carcinoma** (causing hypercalcemia), but it is not seen in Tuberculosis. **High-Yield NEET-PG Pearls:** * **Location:** Secondary TB and SCC are both typically found in the upper lobes (TB in the apex; SCC centrally). * **Most common lung cancer to cavitate:** Squamous Cell Carcinoma. [1] * **Most common lung cancer in non-smokers:** Adenocarcinoma. * **Ghon Complex:** The hallmark of Primary TB (Subpleural focus + lymph node involvement), whereas cavitation is the hallmark of Secondary TB. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337.

Q: Histologic sections of lung (routine H&E stain) reveal alveoli filled with pale, nongranular pink fluid. Neither leukocytes nor erythrocytes are present within this fluid. What is the most likely cause of this abnormality?

Congestive heart failure. ### Explanation **Correct Option: B. Congestive Heart Failure** The description of "pale, nongranular pink fluid" without inflammatory cells (leukocytes) or hemorrhage (erythrocytes) is the classic histological appearance of **Pulmonary Edema (Transudate)**. In Congestive Heart Failure (CHF), increased pulmonary venous hydrostatic pressure forces fluid out of the capillaries into the alveolar spaces [1]. Because the alveolar-capillary membrane remains intact, the fluid is protein-poor (transudate), appearing pale and homogenous on H&E stain. **Analysis of Incorrect Options:** * **A. Bacterial Pneumonia:** This would present as an **exudate**. Histology would show alveoli filled with numerous neutrophils (leukocytes), fibrin, and cellular debris, making the fluid appear granular and dense. * **C. Lymphatic Obstruction:** While this causes edema, it primarily results in **interstitial edema** and dilated lymphatics (lymphangiectasia) rather than uniform alveolar filling [2]. * **D. Pulmonary Embolus:** This typically leads to **pulmonary infarction** or hyemorrhage. Histology would show alveolar spaces filled with erythrocytes (red blood cells) and evidence of ischemic necrosis of the alveolar walls. **NEET-PG High-Yield Pearls:** * **Heart Failure Cells:** In chronic passive congestion (CHF), look for hemosiderin-laden macrophages in the alveoli. * **Transudate vs. Exudate:** Transudates (CHF) have low protein and low LDH; Exudates (Pneumonia/Malignancy) have high protein and high LDH (Light’s Criteria). * **Gross Appearance:** Lungs in pulmonary edema are heavy, boggy, and subcrepitant; frothy blood-tinged fluid exudes from the cut surface. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 536-538. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 124-126.

Q: Which of the following is NOT a feature of asbestosis?

Atelectasis. **Explanation:** Asbestosis is a chronic interstitial lung disease caused by the inhalation of asbestos fibers. The correct answer is **Atelectasis**, as it is not a primary or characteristic feature of asbestos exposure. While "Rounded Atelectasis" can occasionally occur secondary to pleural thickening, generalized atelectasis is not a hallmark of the disease process itself. **Why the other options are incorrect:** * **Pleural Cancer (Mesothelioma):** Asbestos is the most significant risk factor for malignant mesothelioma [1]. It typically occurs after a long latent period (25–40 years). * **Lung Carcinoma:** This is actually the **most common** malignancy associated with asbestos exposure [1]. The risk is synergistically increased (up to 55-fold) in individuals who also smoke. * **Pleural Effusion:** Benign asbestos pleural effusion (BAPE) is often the earliest clinical manifestation of asbestos exposure, occurring within 10–20 years of contact [1]. **Clinical Pearls for NEET-PG:** 1. **Golden-Brown Rods:** Asbestos bodies (Ferruginous bodies) are fibers coated with iron-containing protein, appearing as beaded/dumbell-shaped structures under light microscopy [1]. 2. **Pleural Plaques:** These are the most common manifestation of asbestos exposure; they are well-circumscribed plaques of dense collagen, most often found on the anterior and posterolateral aspects of the parietal pleura and over the diaphragm [1]. 3. **Lower Lobe Predominance:** Unlike silicosis and coal worker's pneumoconiosis (which affect upper lobes), asbestosis primarily involves the **lower lobes** and subpleural regions [1]. 4. **Prussian Blue Stain:** This stain is used to highlight the iron coating of asbestos bodies. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 698-699.

Question 1

Which cells are most important in the causation of asthma?

Accepted Answer

Mast cells

Answer

Macrophages

Answer

Neutrophils

Answer

Lymphocytes

Question 2

Reactivation tuberculosis and primary squamous cell carcinoma of the lung are similar in that they both are commonly associated with:

Accepted Answer

Cavitation

Answer

Scar carcinomas

Answer

Silicosis

Answer

Ectopic secretion of a parathormone-like peptide

Question 3

Mesothelioma is most strongly associated with which variety of asbestos?

Accepted Answer

Amphibole

Answer

Serpentine

Answer

Both serpentine and amphibole asbestos

Answer

Neither serpentine nor amphibole asbestos

Question 4

Histologic sections of lung (routine H&E stain) reveal alveoli filled with pale, nongranular pink fluid. Neither leukocytes nor erythrocytes are present within this fluid. What is the most likely cause of this abnormality?

Accepted Answer

Congestive heart failure

Answer

Bacterial pneumonia

Answer

Lymphatic obstruction by tumor

Answer

Pulmonary embolus

Question 5

Which of the following statements is FALSE regarding malignant mesothelioma?

Accepted Answer

The serpentine type of asbestos is more commonly associated with it than the amphibole type.

Answer

It is the most common tumor of the pleura.

Answer

It is more common in males.

Answer

Vimentin cell marker is positive.

Question 6

What is the most common site of metastasis for carcinoma of the bronchus?

Accepted Answer

Liver and bones

Answer

Prostate

Answer

Kidney

Answer

Breast

Question 7

In lobar pneumonia, the presence of fibrinosuppurative exudate with disintegration of red cells is seen in which stage?

Accepted Answer

Grey hepatization

Answer

Congestion

Answer

Red hepatization

Answer

Resolution

Question 8

Which of the following is NOT a feature of asbestosis?

Accepted Answer

Atelectasis

Answer

Pleural cancer

Answer

Lung carcinoma

Answer

Pleural effusion

Question 9

Which of the following is a neuroendocrine lesion of the lung?

Accepted Answer

Carcinoid

Answer

Benign tumourlets

Answer

Bronchoalveolar carcinoma

Answer

Hemangioma

Question 10

Which is not an inflammatory stage in pneumonia?

Accepted Answer

Organisation

Answer

Congestion

Answer

Resolution

Answer

Hepatisation

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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