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: A 5-year-old child is exposed to Mycobacterium tuberculosis. A month later, the child's tuberculin skin test is positive. The child then develops fever, inspiratory stridor, and nonproductive cough. Which of the following findings is most likely to be present on the chest radiograph of this child?

Hilar lymphadenopathy. **Explanation:** The clinical presentation describes **Primary Tuberculosis** in a child. When a person is first exposed to *Mycobacterium tuberculosis*, the initial response is the formation of a **Ghon complex** [1]. **Why Hilar Lymphadenopathy is correct:** In children, the primary infection is characterized by a small parenchymal lesion (Ghon focus) and, more prominently, significant **hilar or paratracheal lymphadenopathy** [1]. The child’s symptoms of **inspiratory stridor** and nonproductive cough are classic indicators of "Epituberculosis," where enlarged hilar lymph nodes compress the tracheobronchial tree, leading to airway obstruction or collapse. **Analysis of Incorrect Options:** * **B. Miliary pulmonary nodules:** This represents hematogenous dissemination of the bacilli. While possible in primary TB, it is a complication rather than the most likely initial radiographic finding in a child with obstructive symptoms. * **C. Pneumonic consolidation:** While a Ghon focus is a localized area of inflammation, lobar consolidation is more typical of bacterial pneumonia or progressive primary TB, not the classic presentation of nodal compression. * **D. Upper lobe cavitation:** This is the hallmark of **Secondary (Reactivation) Tuberculosis**, typically seen in adults. Primary TB in children is characterized by a lack of cavitation due to a different immune response. **NEET-PG High-Yield Pearls:** * **Ghon Focus:** Subpleural lesion in the upper part of the lower lobe or lower part of the upper lobe [1]. * **Ghon Complex:** Ghon focus + Lymphangitis + Hilar Lymphadenopathy [1]. * **Ranke Complex:** A radiologically visible calcified Ghon complex. * **Primary TB** is "Ghon-centric" (nodes > parenchyma), while **Secondary TB** is "Cavitary-centric" (apex of lungs). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 379-380.

Q: Pneumonia alba is due to which of the following?

Treponema Pallidum. **Explanation:** **Pneumonia alba** is a characteristic pathological finding in **Congenital Syphilis**, caused by the spirochete ***Treponema pallidum***. The term "alba" (Latin for white) refers to the pale, heavy, and firm appearance of the lungs. This occurs because the lungs are consolidated and airless due to massive mononuclear cell infiltration and diffuse interstitial fibrosis, which obliterates the alveolar spaces. **Why the other options are incorrect:** * **Klebsiella pneumoniae:** Typically causes "Friedlander’s pneumonia," characterized by a thick, mucoid, blood-tinged "currant jelly" sputum and a tendency for abscess formation and bulging fissures on X-ray. * **Streptococci (S. pneumoniae):** The classic cause of lobar pneumonia, progressing through stages of congestion, red hepatization, grey hepatization, and resolution. It does not produce the fibrotic "white lung" seen in syphilis. * **Staphylococci (S. aureus):** Usually causes bronchopneumonia often complicated by lung abscesses, pneumatoceles (especially in children), and empyema. **High-Yield Clinical Pearls for NEET-PG:** * **Congenital Syphilis Triad (Hutchinson’s Triad):** Interstitial keratitis, sensorineural deafness (8th nerve), and Hutchinson’s teeth (notched incisors). * **Other Pathological Signs:** Mulberry molars, Saddle nose deformity, Sabre shin (bowing of the tibia), and Clutton’s joints (painless symmetrical knee swelling). * **Histopathology of Syphilis:** The hallmark is **endarteritis obliterans** (narrowing of small arteries) with a plasma cell-rich infiltrate. * **Diagnosis:** Screening is done via VDRL/RPR; confirmation via FTA-ABS or TP-PA.

Question 1

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 2

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 3

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 4

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 5

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 6

Which of the following hormones is elaborated by small cell carcinoma of the lung?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Answer

Parathyroid hormone (PTH)

Answer

Erythropoietin

Answer

Noradrenaline

Question 7

A 5-year-old child is exposed to Mycobacterium tuberculosis. A month later, the child's tuberculin skin test is positive. The child then develops fever, inspiratory stridor, and nonproductive cough. Which of the following findings is most likely to be present on the chest radiograph of this child?

Accepted Answer

Hilar lymphadenopathy

Answer

Miliary pulmonary nodules

Answer

Pneumonic consolidation

Answer

Upper lobe cavitation

Question 8

Which is not an inflammatory stage in pneumonia?

Accepted Answer

Organisation

Answer

Congestion

Answer

Resolution

Answer

Hepatisation

Question 9

Pneumonia alba is due to which of the following?

Accepted Answer

Treponema Pallidum

Answer

Klebsiella

Answer

Streptococci

Answer

Staphylococci

Question 10

In ARDS, which cells are primarily damaged?

Accepted Answer

Type 1 pneumocytes

Answer

Type 2 pneumocytes

Answer

Clara cells

Answer

Alveolar macrophages

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?