Pneumoconiosis
Definition
- Lung disease caused by inhaled mineral dust particles
Diagnostic Criteria
- Some of the major types of pneumoconiosis are covered briefly here
- For more complete coverage, see Biblilography at left
- Coal workers pneumoconiosis (CWP)
- Damage caused by inhaled carbon particles
- Simple CWP
- In its pure form, carbon is essentially non-fibrogenic
- Dust macules
- 0.5-6 mm collection of macrophages
- Carbon particles are seen in both macrophages and free in the tissue
- Principally located along bronchovascular bundles
- No significant fibrosis
- Foci of centrilobular emphysema
- Forms adjacent to carbon particles
- Complicated CWP
- Occurs when mixed with silica and/or silicates resulting in fibrotic lesions
- Mineral dust airway disease
- Haphazard collagen with carbon free and in macrophages
- Progressive massive fibrosis
- Fibrotic nodule/mass ≥1 cm
- May result from fused smaller nodules or diffuse fibrosis
- Rheumatoid pneumoconiosis
- Must have rheumatoid arthritis or Rh factor
- Must have large cavitating nodules
- Eosinophilic necrotic debris
- Surrounded by fibroblasts, histiocytes, giant cells
- Silicosis
- Damage caused by inhalation of crystalline silica
- Acute silicoproteinosis is very rare
- Resembles pulmonary alveolar proteinosis
- Chronic silicosis is characterized by fibrotic nodules
- Sharply demarcated, hypocellular, hyalinized nodules
- Lamellated collagen
- Silica shows weakly birefringent needles
- Nodules may fuse to produce progressive massive fibrosis
- Mixed dust pneumoconiosis
- Damage caused by inhalation of mixtures containg silica and silicates
- Silica shows weakly birefringent needles
- Silicates show strongly birefringent plates
- Macules of interstitial macrophages
- Mixed dust fibrotic lesions
- Stellate lesions of macrophages and varying amounts of collagen
- Has been termed "medusa head" because of extension into adjacent interstitium
- Silicotic nodules
- Progressive massive fibrosis
- Fibrosis ≥1 cm
- Forms a spectrum with CWP and silicosis
- Damage caused by inhalation of mixtures containg silica and silicates
- Silicatosis
- Damage caused by inhalation of non-asbestos silicates
- Includes talc, kaolin, mica, feldspars
- Strongly birefringent plates
- Findings similar to those of mixed dust pneumoconiosis
- Granulomatous reaction may also be seen
- Diffuse interstitial fibrosis may also be seen
- May represent fused nodules
- May resemble UIP
- Damage caused by inhalation of non-asbestos silicates
- Asbestosis
- Damage caused by inhaled asbestos fibers
- Diffuse interstitial fibrosis, usually resembling usual interstitial pneumonia (UIP)
- Fewer fibroblastic foci
- Associated with pleural plaques
- Asbestos bodies
- Iron positive beads on a translucent core
- Carbon and silicates may also ferruginate, but the core is different
- Diagnosis requires ≥2 asbestos bodies per square cm and interstitial fibrosis
- Berylliosis
- T cell hypersensitivity reaction
- Closely resembles sarcoidosis
- Well formed granulomas with mild to moderate inflammation
- Present along bronchovascular bundles
- Diagnosed by history and T cell activation test
- Hard metal disease
(giant cell interstitial pneumonia)
- Damage caused by inhaled cobalt, usually as hard metal dust
- Birefringent black intracellular particles
- Patchy filling of air spaces by macrophages and multinucleated giant cells
- Giant cells frequently ingest macrophages
- Multinucleated alveolar lining cells may be present
- If giant cells are rare, resembles DIP
- Foci of centrilobular fibrosis and interstitial inflammatory infiltrate
- BOOP-like changes may be present
- Damage caused by inhaled cobalt, usually as hard metal dust
Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
