Pneumoconioses (General)
Epidemiology and Etiology:
- Inhalation of dusts
- Inorganic dusts in the workplace mostly
- Particles with a size range of 1 to 5 um have
the highest probability of deposition and retention within the
respiratory tract
- Different substances tend to have different
responses
- Crytstalline silica is highly fibrogenic
- Carbon is an innocuous “nuisance” dust
- Many of the dusts have a characteristic
reaction pattern or appearance in histologic sections which permits an
accurate diagnosis
- Evolve over several decades
Common sites:
Gross features:
Histologic features:
- Fibrosis generally
- Polarizing microscopy:
- Silicosis: faintly birefringent particulates,
larger, brightly birefringent particles maybe
- Sarcoidosis: large platy birefringent particles,
typical for calcium oxalate.
Endogenous calcium carbonate are smaller and sparser needle-like
particles than talc
- Coal worker’s pneumoconiosis: partial
polarization shows a mixture of faintly and brightly birefringent particles
superimposed on black pigment
- Asbestosis: not useful for the detection of
asbestos
- Silicatosis: numerous brightly birefringent particulates associated with
macrophages or within stellate lesions
- Mixed dust pneumoconiosis: mixed dust fibrotic
nodules show particles with variable birefringence
- Talcosis: characteristic needle-like morphology. Larger platy particles are seen in IV talcosis and talco pleurodesis
- Siderosis: typically nonrefringent iron oxide
pigment
- Aluminosis: nonrefringent aluminum dust
- Hard metal pneumoconiosis: not readily
identified by polarization
- Berylliosis: not useful
- Rare earth pneumoconiosis: birefringent cerium
oxide
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- No specific treatment is available, but proper
diagnosis is crucial for accurate determination of prognosis and, when
indicated, compensation
- Analytic electron microscopy is a powerful tool
for identification of dusts in lung tissue samples
References:
- Leslie KO, Wick MR. Practical Pulmonary Pathology: A
Diagnostic Approach, 2nd ed. (2011)