Skip directly to site content Skip directly to search


Español  Other Languages


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
 Search
		×
			NIOSH
			NIOSH
				All CDC
				Submit
			For a full list of topics:A-Z Index
			Advanced Search
		Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)








Study Syllabus for Classification of Radiographs of Pneumoconioses						Print
																Related Pages
										Pathology OverviewPathology Basis of Occupational Lung DiseaseAsbestos Pleuropulmonary Disease
Unlike the compact mineral particles of silica and coal mine dust, asbestos represents a family of fibrous silicates presenting as thin filaments with a high aspect (length to width) ratio. The 2 mineralogic forms of asbestos are amphiboles (e.g., crocidolite and amosite) and serpentines, of which chrysotile is the only commercially important form. Although restrictions have been placed on the use of asbestos in developed countries, asbestos exposure still remains an important cause of lung and pleural disease in persons previously exposed to airborne asbestos fibers and in those who continue to be exposed in the processing, application or removal of asbestos or its products [“Diagnostic,” 2004].
Because of their irregular or long filamentous configurations, asbestos fibers tend to be deposited at the bifurcation of small airways and subsequently pass into and through bronchiolar walls. Smaller fibers reach the lung parenchyma via the airstream, where they can penetrate alveolar septa or the visceral pleura [Churg 1998a]. Amphibole asbestos is durable within the lung, whereas chrysotile degrades over time because of the leaching of magnesium ions. Short asbestos fibers may be phagocytized by alveolar macrophages and subsequently removed from the lung by means of airways or lymphatics [Churg 1998a]. A relatively minor proportion of larger fibers are coated with protein and iron by alveolar macrophages to form asbestos bodies [Roggli 2004]. Unlike uncoated fibers, asbestos bodies can be readily recognized by light microscopy in slides of lung tissue and serve as valuable markers of asbestos exposure (Fig. 32). Histochemical stains for iron enhance the recognition and detection of asbestos bodies in tissue. Asbestos is fibrogenic to the lung and pleura, is a recognized cause of lung carcinoma, and is the most important cause of pleural mesothelioma [Roggli et al. 2010].
Asbestosis
Asbestosis is defined as lung parenchymal fibrosis due to inhaled asbestos fibers [“Diagnostic,” 2004; Churg 1998a; Roggli et al. 2010]. Macroscopically, the lung is remodeled by interstitial fibrosis and honeycombing, frequently with a lower-lobe distribution, imparting an appearance similar to that of idiopathic pulmonary fibrosis. Coarse gray fibrous trabeculae and fibrotic interlobular septa extend into the lung parenchyma, which often has a bronze discoloration in the fixed specimen (Fig. 33). Histologically, the extent (and progression) of fibrosis is graded from 1 (fibrosis confined to the walls of respiratory bronchioles and the first tier of adjacent alveoli) to 4 (honeycomb changes) [Roggli et al. 2010]. Fibrosis histologically has a chronic collagenous appearance with low cellularity and irregular effacement of alveolar architecture, which gives rise to small irregular opacities in the chest radiograph [Dick et al. 1992] (Fig. 34). Two or more asbestos bodies per square centimeter of a 5-mm thick lung section, in combination with interstitial fibrosis of the appropriate pattern, are indicative of asbestosis (Fig. 32). Fewer asbestos bodies do not necessarily exclude a diagnosis of asbestosis, but evidence of excess asbestos would then require quantitating fibers by electron microscopy following lung digestion and sediment extraction [Roggli et al. 2010; Roggli and Sharma 2004].PNEUMOCONIOSISPage 1 of 5ASBESTOS-INDUCED BENIGN PLEURAL DISEASE
							
					
							Last Reviewed:  April 26, 2023						Source: 	National Institute for Occupational Safety and Health
					Facebook
        Twitter
        LinkedIn
        Syndicate homeStudy Syllabus for Classification of Radiographs of Pneumoconioses
Introductionplus icon
Preface
Appreciation to Contributors
Intent of the Self-study Syllbus
Getting Started
Clinical Overviewplus icon
Major Occupational Lung Diseasesplus icon
Pneumoconioses
Central Role of Diagnostic Imagingplus icon
Role of CT
Overview of Nonimaging Clinical Tools in Lung Disease Diagnosis
Appendix A
References
Pathology Overviewplus icon
Pulmonary Silicosis
Coal Workers’ Pneumoconiosis
Asbestos Pleuropulmonary Disease
Pathological-Clinical Correlations
References
Radiograph Classificationplus icon
SUBSET 1 – Radiograph Classification, #1 to #19plus icon
Introduction
Radiograph Identification
Section 1: Image Quality
Section 2: Parenchymal Abnormalities, #1 to #14
Section 3: Pleural Abnormalities, #15 to #19
Section 4: Any Other Abnormalities
Section 5
SUBSET 2 – Radiograph #20 to #27plus icon
Radiograph #20
Radiograph #21
Radiograph #22
Radiograph #23
Radiograph #24
Radiographs #25 to #27
SUBSET 3 – Radiograph #28 to #38plus icon
Radiographs #28 to #30
Radiographs #31 to #32
Radiographs #33 to #35
Radiographs #36 to #38
SUBSET 4 – Radiograph #39 to #46 (Small and Large Opacities)plus icon
Radiographs #39 to #40
Radiographs #41 to #42
Radiographs #43 to #44
Radiograph #45
Radiograph #46
SUBSET 5 – Classifications and Answer Keys, Radiographs #47 to #83
Quiz Follow NIOSH Facebook
Pinterest
Twitter
YouTube
 NIOSH Homepage NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs
Contact NIOSH


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue