Asbestos-related disease
- Lesion
Asbestos fibres scar the lower lungs, make pleural plaques, and cause lung carcinoma and mesothelioma decades after exposure.
What it is
Asbestos is a group of fibrous silicates once widely used in construction, insulation, brakes and shipbuilding. The fibres reach the alveoli, resist clearance and keep macrophages activated. The result is a family of diseases: pleural plaques (the commonest), effusions, diffuse interstitial fibrosis (asbestosis), lung carcinoma and malignant mesothelioma, with long latency. Smoking multiplies the lung cancer risk but not the mesothelioma risk.
Structure
- Asbestosis: fibrosis around respiratory bronchioles and alveolar ducts that spreads into alveoli; UIP-like pattern with fibroblastic foci and honeycombing.
- Asbestos bodies in the fibrotic areas distinguish it from other fibrosis.
- Pleural plaque: pearly white, discrete plaque; microscopy shows acellular, basket-weave hyalinised collagen, often calcified.
- Associated carcinoma or mesothelioma with typical features.
Step by step
- Long, thin fibres reach the distal lung and cannot be fully engulfed by macrophages (frustrated phagocytosis).
- Macrophages stay activated, release oxidants, IL-1 and TGF-β, and some fibres become coated with iron (asbestos bodies).
- Fibroblasts lay down collagen around bronchioles and ducts, extending into a diffuse lower-lobe fibrosis.
- Fibres migrate to the pleura and cause plaques, effusions and, over decades, mesothelioma.
- Fibres adsorb carcinogens (as in tobacco smoke) and generate free radicals: tumour initiation and promotion.
- The scarring narrows pulmonary arteries: pulmonary hypertension and cor pulmonale.
Markers
- Asbestos bodies (Prussian blue)
Clinical notes
- Dyspnoea appears 10 to 30 years after exposure; lower-zone linear opacities and honeycombing on imaging.
- Plaques are usually silent and seen as calcified densities on the chest film.
- Asbestos is banned in many countries; Colombia banned it by law in 2019, but exposure from old buildings and products persists.
Test yourself
Think of the answer, then tap the question to see it.
What is the most common manifestation of asbestos exposure?
Pleural plaques: well-circumscribed, often calcified plaques of dense collagen on the parietal pleura and diaphragm.
How does the distribution of asbestosis differ from silicosis?
Asbestosis starts in the lower lobes and subpleurally, whereas silicosis and coal disease favour the upper zones.
Does smoking increase the mesothelioma risk of asbestos workers?
No. Smoking multiplies their lung carcinoma risk but does not increase the risk of mesothelioma.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Asbestos (MedlinePlus, US National Library of Medicine, 2025); Mesothelioma (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.