PA25.7 | Lung Disease & Tumour Morphology — Practical — Summary & Reflection

REFLECT

Now that you have reviewed the full spectrum of lung pathology for this practical:

1. Which two conditions did you find most difficult to distinguish on microscopy alone, and what single feature would you use to tell them apart in an exam spot?
2. Think of a patient scenario where knowing the histological subtype of lung cancer would change management. Which histotype would you NOT treat with surgery alone?
3. In the 2x2 panel grid, if you had only Panel C (SCLC) to examine, list three morphological features in order of the strongest to weakest diagnostic weight.

KEY TAKEAWAYS

Lung Pathology Practical — Core Recognition Points

• Lobar pneumonia = lobe-sized consolidation, alveolar neutrophil + fibrin exudate, intact walls; stages: congestion → red → grey hepatisation → resolution.
• Bronchopneumonia = patchy, airway-centred, purulent; intervening aerated lung.
• TB = caseating granuloma (caseation + epithelioid macrophages + Langhans giant cells + lymphocyte cuff); Ghon complex (primary); cavitation (post-primary); ZN for AFB.
• Emphysema = alveolar wall destruction, bullae gross; septal loss on micro; no exudate.
• Anthracosis = carbon macrophages; silicosis = laminated collagen whorls + birefringence; asbestosis = ferruginous bodies + lower-lobe fibrosis.
• SCLC = small hyperchromatic cells, scant cytoplasm, nuclear moulding, crush artefact; central mass.
• SCC = keratin pearls, intercellular bridges; central mass, may cavitate.
• Adenocarcinoma = gland formation, mucin, TTF-1+; peripheral/subpleural.
• Mesothelioma = pleural rind (encasing, not invading); calretinin+, CEA−; asbestos-related.
• Reading sequence: gross architecture → micro pattern → infective/neoplastic/reactive → name + subtype.