Respiratory Pathology Practice Questions

Q: Which of the following is a tumor marker for lung cancer?

CEA. **Explanation:** **Carcinoembryonic Antigen (CEA)** is the correct answer. It is a glycoprotein primarily associated with colorectal carcinoma but is also a well-recognized tumor marker for **Adenocarcinoma of the lung**. While not specific enough for initial diagnosis, CEA levels are clinically significant for monitoring treatment response, detecting recurrence, and predicting prognosis in non-small cell lung cancer (NSCLC) [1]. **Analysis of Incorrect Options:** * **S-100:** This is a marker for cells derived from the neural crest. It is highly sensitive for **Melanoma**, Schwannomas, and Langerhans Cell Histiocytosis (LCH). * **CD-99 (MIC2):** This is a highly specific cell surface marker for **Ewing’s Sarcoma** and Primitive Neuroectodermal Tumors (PNET). * **Beta 2 microglobulin:** This marker is primarily used in hematological malignancies, most notably **Multiple Myeloma** and certain lymphomas, to determine tumor burden and prognosis. **High-Yield Clinical Pearls for NEET-PG:** * **Adenocarcinoma** is now the most common histological subtype of lung cancer in both smokers and non-smokers. * **IHC Markers for Lung Cancer:** * **Adenocarcinoma:** TTF-1 (Thyroid Transcription Factor-1) and Napsin A. * **Squamous Cell Carcinoma:** p40, p63, and Cytokeratin 5/6. * **Small Cell Carcinoma:** Chromogranin A, Synaptophysin, and CD56 (Neural Cell Adhesion Molecule). * CEA is also elevated in heavy smokers without malignancy, which must be considered during clinical correlation [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 346.

Q: Reactivated tuberculosis is most commonly located near which anatomical region?

Apex. **Explanation:** **Correct Option: A (Apex)** Reactivated (Secondary) Tuberculosis typically localizes to the **apex of the upper lobes** (or the superior segments of the lower lobes) [1]. This predilection is due to the high **Ventilation-Perfusion (V/Q) ratio** found in the apices. *Mycobacterium tuberculosis* is an obligate aerobe; the higher alveolar oxygen tension ($P_AO_2$) in the apex provides an ideal environment for the bacilli to flourish after reactivation of a latent focus. **Analysis of Incorrect Options:** * **B. Bronchus:** While TB can spread via the endobronchial route (causing endobronchial TB), it is a complication or a mode of spread rather than the primary site of reactivation [1]. * **C. Subpleural region:** This is the characteristic location of the **Ghon focus** in **Primary Tuberculosis**, typically found in the lower part of the upper lobe or upper part of the lower lobe [1]. * **D. Base:** The bases have a lower V/Q ratio and lower oxygen tension compared to the apices, making them less favorable for the growth of reactivation TB. **NEET-PG High-Yield Pearls:** * **Ghon Complex:** Consists of a parenchymal subpleural lesion (Ghon focus) + draining lymphadenopathy [1]. * **Ranke Complex:** A radiologically visible healed Ghon complex that has undergone calcification. * **Assmann Focus:** The specific infraclavicular lesion seen in secondary TB. * **Simon’s Focus:** Apical nodules formed during hematogenous seeding in primary TB that later serve as the site for secondary reactivation. * **Morphology:** Secondary TB is characterized by **caseous necrosis** and **cavitation**, which is less common in primary TB (except in immunocompromised patients) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 319-321.

Question 1

Which type of shock is characterized by the development of 'shock lung'?

Accepted Answer

Septic shock

Answer

Hypovolemic shock

Answer

Anaphylactic shock

Answer

Neurogenic shock

Question 2

Which of the following does not cause cavitation in the lung parenchyma?

Accepted Answer

Hamartoma

Answer

Squamous cell carcinoma

Answer

Tuberculosis

Answer

Staphylococcus pneumonia

Question 3

Bronchocentric granulomatosis commonly occurs due to?

Accepted Answer

Hypersensitivity reaction to Aspergillus

Answer

Immunological reaction to HIV

Answer

Damage by c-ANCA

Answer

Damage by p-ANCA

Question 4

What is the characteristic histopathological feature of Pneumocystis carinii pneumonia?

Accepted Answer

Mononuclear cells in bronchoalveolar lavage

Answer

Interstitial pneumonitis

Answer

Increased eosinophils

Answer

Foamy vacuolated exudates

Question 5

In hyaline membrane disease, what is the primary pathological component in the lung?

Accepted Answer

Fibrin

Answer

Albumin and complement

Answer

Precipitated surfactant

Answer

Mucus

Question 6

Which of the following is a tumor marker for lung cancer?

Accepted Answer

CEA

Answer

S-100

Answer

CD-99

Answer

Beta 2 microglobulin

Question 7

Pneumatocele is most commonly caused by which organism?

Accepted Answer

Staphylococcus

Answer

Streptococcus

Answer

Streptococcus pneumoniae

Answer

P. carnii

Question 8

Reactivated tuberculosis is most commonly located near which anatomical region?

Accepted Answer

Apex

Answer

Bronchus

Answer

Subpleural region

Answer

Base

Question 9

Asbestosis causes all of the following except?

Accepted Answer

Hilar lymphadenopathy

Answer

Shaggy heart borders

Answer

Honeycombing

Answer

Basal peribronchial fibrosis

Question 10

Asbestosis of the lung is associated with all of the following EXCEPT?

Accepted Answer

Nodular lesions involving upper lobe

Answer

Mesothelioma

Answer

Progression of lesion even after stopping exposure to asbestos

Answer

Asbestos bodies in sputum

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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