Lung
Pneumoconiosis
Asbestosis
Author: Elliot Weisenberg, M.D.
Last author update: 1 September 2011
Last staff update: 20 August 2020
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed search: asbestosis [title] pneumoconiosis pulmonary
Table of Contents
Definition / general | Asbestos | Gross images | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Weisenberg E. Asbestosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungnontumorasbestosis.html. Accessed April 23rd, 2024.
Definition / general
- Similar to other pneumoconiosis
- Initial injury is at bifurcations of small airways and ducts; macrophages ingest fibers, release chemotactic factors and fibrogenic mediators, causing interstitial fibrosis similar to other fibrosing lung diseases such as UIP
- Begins around respiratory bronchioles and alveolar ducts, extends distally; eventually causes honeycomb lungs
- Begins in lower lobes and subpleurally (in contrast to coal workers' pneumoconiosisP and silicosis), progresses to middle and upper lobes
- Visceral pleura becomes fibrotic, may bind lung to chest wall; may have associated Caplan syndrome
- Symptoms: usually begin after 10 years of exposure, initially shortness of breath with exertion and later at rest; may progress to heart failure
- Pleural plaques: well circumscribed plaques of dense collagen, often with calcium; on parietal pleura and dome of diaphragm; do not contain asbestos bodies, but rare if no asbestos history; may induce pleural effusions, usually no symptoms
- Asbestos fiber detection: H&E, Prussian blue, incineration and EM
Asbestos
- Crystalline hydrated silicates that form fibers
- Causes localized fibrous plaques, pleural effusions, parenchymal interstitial fibrosis (asbestosis), bronchogenic carcinoma, mesothelioma, laryngeal carcinoma and possibly colon carcinoma
- Increased incidence of mesothelioma in families of asbestos workers
- Exists in serpentine / chrysotile (curly, flexible) and amphibole (straight, stiff, brittle) forms; most asbestos in industry are serpentine, but amphiboles are more pathogenic; link with mesothelioma is almost always with amphibole form
- Chrysotiles usually are caught in upper respiratory passages, removed by mucociliary elevator; they are soluble and leached from tissue if they reach alveoli
- Amphiboles (straight, stiff) go deeper into lungs; fibers > 8 mm and thinner than 0.5 mm are more injurious
- Both types are fibrogenic; act as tumor initiator and promoter; generate free radicals; toxic chemicals (tobacco smoke) may also be adsorbed to asbestos fibers
- Asbestos may act by countering antioxidant effect of Vitamin C (ascorbic acid) (Hum Pathol 2003;34:737)
- Relative risks compared to normal population: asbestos and bronchogenic carcinoma has RR of 5; with tobacco use, RR is 55
- Asbestos and mesothelioma (pleural, pericardial, peritoneal) has RR of 1000; no increased risk with smoking
- Incidence of mesothelioma expected to increase until 2020 - 2025 due to lag time between exposure and diagnosis
- Note: asbestos related tumors have no special histologic features
Gross images
Images hosted on other servers:
Pleural plaque
Microscopic (histologic) description
- Early: interstitial pneumonia with desquamative features, hyperplastic alveolar cells with intracytoplasmic Mallory's hyaline tissue
- Later: diffuse interstitial fibrosis with honeycombing (silicosis is nodular), asbestos bodies (golden brown, fusiform or beaded rods with translucent center; asbestos fibers coated with iron-containing proteinaceous material); iron from phagocyte ferritin
- Asbestos fibers may have oxalate crystal deposition (Hum Pathol 2003;34:737)
- Ferruginous bodies: inorganic particulates coated with phagocyte ferritin
Microscopic (histologic) images
Contributed by Jijgee Munkhdelger, M.D., Ph.D. and Andrey Bychkov, M.D., Ph.D.
Asbestos bodies in alveolar spaces
Ferruginous body
Asbestos body
Dumbbell shaped asbestos body
