Lung - nontumor

Topic Completed: 1 September 2011

Revised: 30 January 2019, last major update September 2011

Copyright: (c) 2003-2017,, Inc.

PubMed search: asbestos [title] pneumoconiosis pulmonary

Elliot Weisenberg, M.D.
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Table of Contents
Definition / general
Cite this page: Weisenberg E. Asbestos. website. Accessed May 28th, 2020.
Definition / general
  • 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
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