A 27-year-old HIV-negative construction worker has had cough, evening fever and weight loss for 2 months. Chest X-ray shows a cavity in the right apex. A biopsy shows granulomas with central amorphous, cheesy necrosis surrounded by epithelioid cells and Langhans giant cells. Which process mainly produces this necrosis?

Delayed hypersensitivity driven by Th1 cells

IgE-mediated release of mast cell mediators

Direct cytotoxicity of a mycobacterial exotoxin

Immune-complex deposition in vessel walls

Respiratory pathology including lung cancer

19 NEET-PG practice questions on Respiratory pathology including lung cancer, part of Pathology. The first 19 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
A 9-year-old boy from a slum in Mumbai dies in a road accident. At autopsy there is a 1 cm subpleural caseous nodule in the lower part of the right upper lobe, with enlarged caseous right hilar lymph nodes. What is this combination of lesions called?
1. AAssmann focus
2. BRich focus
3. CSimon focus
4. DGhon complex
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Answer: D · Ghon complex
A subpleural caseous focus near the interlobar fissure (the Ghon focus) together with the involved draining hilar nodes is the Ghon complex of primary tuberculosis. In most immunocompetent children cell-mediated immunity contains it, and it heals by fibrosis and later calcification. It is a marker of infection rather than active disease in most people. Progressive primary tuberculosis is mainly seen in young children, malnutrition and HIV.
- A: An Assmann focus is an infraclavicular lesion of post-primary (secondary) tuberculosis.
- B: A Rich focus is a caseous cortical focus in the brain whose rupture causes tuberculous meningitis.
- C: A Simon focus is an apical seeding focus from primary infection that can later reactivate.
Question 2 · Medium
A 27-year-old HIV-negative construction worker has had cough, evening fever and weight loss for 2 months. Chest X-ray shows a cavity in the right apex. A biopsy shows granulomas with central amorphous, cheesy necrosis surrounded by epithelioid cells and Langhans giant cells. Which process mainly produces this necrosis?
1. AIgE-mediated release of mast cell mediators
2. BDirect cytotoxicity of a mycobacterial exotoxin
3. CImmune-complex deposition in vessel walls
4. DDelayed hypersensitivity driven by Th1 cells
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Answer: D · Delayed hypersensitivity driven by Th1 cells
This is post-primary (secondary) tuberculosis, which favours the apices and cavitates. Mycobacterium tuberculosis has no classic exotoxin; tissue damage comes from the host's cell-mediated response. Th1 cells secrete interferon-gamma, which activates macrophages to form granulomas, and the same delayed (type IV) hypersensitivity produces caseous necrosis and cavitation. This is why people with low CD4 counts often have poorly formed granulomas and less cavitation.
- A: Type I hypersensitivity does not produce granulomas or caseous necrosis.
- B: M. tuberculosis does not damage tissue through a secreted exotoxin.
- C: Immune-complex vasculitis is a type III mechanism, not the basis of caseation.
Question 3 · Easy
A 64-year-old man who worked for 25 years in an asbestos-cement sheet factory in Gujarat has a thick rind of tumour encasing the left lung. Pleural biopsy shows a malignant tumour with tubulopapillary and spindle-cell areas. Which immunohistochemical marker supports mesothelioma rather than metastatic adenocarcinoma?
1. ACalretinin
2. BSynaptophysin
3. CCDX2
4. DTTF-1
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Answer: A · Calretinin
Malignant mesothelioma is positive for mesothelial markers such as calretinin, WT1, cytokeratin 5/6 and D2-40, and negative for adenocarcinoma markers such as TTF-1 and CEA. A panel of positive and negative markers is used because no single stain is perfect. Asbestos exposure, usually decades earlier, is the main risk factor, and the tumour spreads over the pleural surface to encase the lung. Smoking does not add to the mesothelioma risk, unlike its effect on lung carcinoma.
- B: Synaptophysin marks neuroendocrine tumours such as small cell carcinoma and carcinoid.
- C: CDX2 marks intestinal adenocarcinoma, such as colorectal metastases.
- D: TTF-1 marks lung adenocarcinoma (and thyroid tumours) and is negative in mesothelioma.
Question 4 · Medium
A 29-year-old non-smoking woman has had three episodes of right lower lobe pneumonia in a year and occasional streaks of blood in her sputum. Bronchoscopy shows a smooth, red, polypoid mass blocking the right lower lobe bronchus. Biopsy shows nests of uniform cells with finely stippled chromatin, rare mitoses and no necrosis; chromogranin and synaptophysin are positive. What is the diagnosis?
1. AMucoepidermoid carcinoma
2. BSmall cell carcinoma
3. CPulmonary hamartoma
4. DTypical carcinoid tumour
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Answer: D · Typical carcinoid tumour
A young non-smoker with an endobronchial polypoid mass, recurrent obstructive pneumonia and haemoptysis, and uniform neuroendocrine cells with very few mitoses and no necrosis, has a typical carcinoid tumour. Carcinoids are low-grade neuroendocrine tumours; atypical carcinoids have more mitoses or focal necrosis, and small cell carcinoma is the high-grade end of the spectrum. Carcinoid syndrome is uncommon with bronchial tumours without liver metastasis. Surgical resection is usually curative.
- A: Mucoepidermoid carcinoma has mucin-secreting and squamoid cells and is not chromogranin-positive.
- B: Small cell carcinoma shows many mitoses, extensive necrosis and occurs in heavy smokers.
- C: A hamartoma is a peripheral coin lesion of cartilage and fat, not a neuroendocrine tumour.
Question 5 · Hard
A 38-year-old software engineer from Bengaluru who has never smoked has a left lower lobe mass with pleural and bone metastases. Biopsy shows a mucin-producing adenocarcinoma with some signet-ring cells. Molecular testing shows no EGFR mutation, and immunohistochemistry is strongly positive for ALK. Which drug is the most appropriate first-line systemic therapy?
1. ACetuximab
2. BAlectinib
3. COsimertinib
4. DTrastuzumab
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Answer: B · Alectinib
A young never-smoker with a mucinous, signet-ring adenocarcinoma is the typical setting for an ALK gene rearrangement (often EML4-ALK), which IHC here confirms. The fusion produces a constitutively active tyrosine kinase, and an ALK inhibitor such as alectinib gives much better responses than chemotherapy, including in brain metastases. Crizotinib was the first drug of this class. Driver testing for EGFR, ALK, ROS1 and others is done on every advanced non-squamous NSCLC before treatment.
- A: Cetuximab is an anti-EGFR antibody used in colorectal and head and neck cancers, not ALK lung cancer.
- C: Osimertinib inhibits mutant EGFR, which this tumour does not carry.
- D: Trastuzumab targets HER2, used mainly in breast and gastric cancer.
Question 6 · Easy
A 46-year-old daily-wage labourer dies in a district hospital on day 6 of a pneumococcal pneumonia that was treated late. At autopsy the whole right lower lobe is firm, dry and grey-brown on the cut surface. Microscopy shows alveoli packed with fibrin and neutrophils, with disintegrating red cells. Which stage of lobar pneumonia is this?
1. ARed hepatisation
2. BCongestion
3. CGrey hepatisation
4. DResolution
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Question 7 · Medium
A 49-year-old man with alcohol dependence was found unconscious at home after a binge 3 weeks ago. He now has fever and coughs up large amounts of foul-smelling sputum. He has poor dental hygiene. Chest X-ray shows a thick-walled cavity with an air-fluid level in the posterior segment of the right upper lobe. What is the most likely mechanism of this lesion?
1. ACavitation within an obstructing bronchial carcinoma
2. BHaematogenous spread from right-sided endocarditis
3. CReactivation of a dormant mycobacterial focus
4. DAspiration of oropharyngeal anaerobic bacteria
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Question 8 · Easy
A 41-year-old schoolteacher from Kolkata who has never smoked has a 3 cm peripheral nodule in the right upper lobe on CT. She has no cough and no other illness. What is the most likely histological type?
1. AAdenocarcinoma
2. BLarge cell carcinoma
3. CSquamous cell carcinoma
4. DSmall cell carcinoma
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Question 9 · Medium
A 61-year-old heavy smoker is admitted with weakness and swelling of both legs for 5 weeks. BP is 168/100 mmHg. He has darkened skin but no striae or central obesity. Serum potassium is 2.5 mmol/L, bicarbonate 34 mmol/L and random glucose 248 mg/dL. Serum cortisol and ACTH are both very high, and CT shows a central lung mass with mediastinal nodes. What is the most likely tumour type?
1. ALarge cell carcinoma
2. BSmall cell carcinoma
3. CSquamous cell carcinoma
4. DAdenocarcinoma
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Question 10 · Medium
At a tumour board in a medical college, a postgraduate makes these statements about lung cancer: 1. Adenocarcinoma is the commonest type in people who have never smoked. 2. EGFR mutations are commoner in adenocarcinomas of never-smoking Asian women. 3. Limited-stage small cell carcinoma is usually treated by surgery alone. 4. Keratin pearls and intercellular bridges identify squamous cell carcinoma. Which statements are correct?
1. A1 and 4 only
2. B1, 2 and 4 only
3. C2 and 3 only
4. D1, 3 and 4 only
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Question 11 · Medium
A 58-year-old smoker in a Chennai medical OPD has difficulty climbing stairs and getting up from a chair for 3 months, with a dry mouth. Knee and ankle jerks are absent but return after he contracts his thigh muscles strongly for 10 seconds. A chest X-ray shows a right hilar mass. What is the mechanism of his weakness?
1. AAntibodies to muscle-specific tyrosine kinase
2. BAntibodies to postsynaptic acetylcholine receptors
3. CAntibodies to presynaptic voltage-gated calcium channels
4. DDirect tumour infiltration of the lumbosacral plexus
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Question 12 · Medium
A 36-year-old woman with advanced HIV (CD4 count 42 cells/µL) who had stopped her antiretroviral therapy has fever, weight loss and enlarged cervical nodes. Xpert MTB/RIF on the node aspirate detects M. tuberculosis without rifampicin resistance. What would a biopsy of the node most likely show?
1. ASheets of macrophages full of bacilli, with no true granulomas
2. BReed-Sternberg cells in a mixed inflammatory background
3. CWell-formed caseating granulomas with scanty bacilli
4. DSarcoid-like non-caseating granulomas with no bacilli
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Question 13 · Medium
A 33-year-old woman has tender red nodules on both shins, ankle pain and a dry cough. Chest X-ray shows bilateral hilar lymphadenopathy. Serum calcium is 11.6 mg/dL with low PTH. A transbronchial biopsy shows tight non-caseating granulomas with negative stains for acid-fast bacilli and fungi. What is the mechanism of her hypercalcaemia?
1. AIncreased renal calcium reabsorption from raised PTH
2. BOsteolytic bone destruction by granulomas
3. CPTH-related protein released by granuloma cells
4. DCalcitriol made by 1-alpha-hydroxylase in granuloma macrophages
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Question 14 · Hard
A 62-year-old man worked for 20 years in an asbestos-cement factory and has smoked 30 pack-years. CT shows calcified pleural plaques on both diaphragms and mild basal fibrosis. A lower-lobe biopsy shows golden-brown beaded rods that stain with Prussian blue. He asks which cancer he is most likely to develop. What is the correct answer?
1. ABronchogenic carcinoma
2. BLaryngeal carcinoma
3. CPeritoneal mesothelioma
4. DMalignant pleural mesothelioma
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Question 15 · Medium
A 67-year-old retired bank clerk has had progressive breathlessness and dry cough for 2 years. He has finger clubbing and fine end-inspiratory crackles at both bases. HRCT shows basal, subpleural reticular shadows with honeycombing and no ground-glass change. A lung biopsy was taken before a trial of therapy. Which histological pattern is expected?
1. ANon-caseating granulomas along lymphatics
2. BPatchy fibrosis of varying age with fibroblastic foci
3. CUniform interstitial fibrosis of the same age
4. DHyaline membranes lining the alveolar ducts
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Question 16 · Hard
A 59-year-old man with a 40 pack-year history has a bronchoscopic biopsy showing small cells with scant cytoplasm, nuclear moulding and crush artefact. The registrar lists conditions to watch for: 1. Hyponatraemia from inappropriate ADH secretion. 2. Cushing syndrome from ectopic ACTH. 3. Lambert-Eaton myasthenic syndrome. 4. Hypercalcaemia from PTH-related protein. Which are recognised paraneoplastic associations of this tumour?
1. A2, 3 and 4 only
2. B1 and 3 only
3. C1, 2 and 3 only
4. D1, 3 and 4 only
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Question 17 · Medium
A 52-year-old man who has kept racing pigeons on his terrace in old Delhi for 15 years has episodes of fever, cough and breathlessness that start a few hours after cleaning the lofts. Lung biopsy shows interstitial lymphocytes and loosely formed non-necrotising granulomas centred on the bronchioles. Which hypersensitivity mechanisms underlie this disease?
1. AType III and type IV reactions
2. BType I reaction alone
3. CType I and type II reactions
4. DType II reaction alone
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Question 18 · Hard
A 20-year-old engineering student in a Pune hostel has had a dry cough, headache and low fever for 10 days. His chest X-ray shows patchy shadows that look worse than his chest examination. Haemoglobin has fallen from 14 to 10.2 g/dL, the direct antiglobulin test is positive for C3 only, and his blood sample clumps when cooled. Which histological pattern would his lung most likely show?
1. AAbscesses with central necrosis and neutrophils
2. BCaseating granulomas with Langhans giant cells
3. CNeutrophil-rich exudate filling the alveoli of one lobe
4. DMononuclear infiltrate in the alveolar septa with clear alveoli
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Question 19 · Medium
For 22 years a 48-year-old labourer broke sandstone blocks in a Rajasthan quarry with no dust mask, and his breathlessness on exertion is getting slowly worse. His chest film shows many small nodules in both upper zones and eggshell calcification of the hilar lymph nodes. Which infection is he at markedly increased risk of?
1. APulmonary nocardiosis
2. BLegionella pneumonia
3. CPulmonary tuberculosis
4. DPneumocystis pneumonia
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Respiratory pathology including lung cancer

A 9-year-old boy from a slum in Mumbai dies in a road accident. At autopsy there is a 1 cm subpleural caseous nodule in the lower part of the right upper lobe, with enlarged caseous right hilar lymph nodes. What is this combination of lesions called?

A 41-year-old schoolteacher from Kolkata who has never smoked has a 3 cm peripheral nodule in the right upper lobe on CT. She has no cough and no other illness. What is the most likely histological type?

A 36-year-old woman with advanced HIV (CD4 count 42 cells/µL) who had stopped her antiretroviral therapy has fever, weight loss and enlarged cervical nodes. Xpert MTB/RIF on the node aspirate detects M. tuberculosis without rifampicin resistance. What would a biopsy of the node most likely show?