anthracotic pigment
Summary
Black carbon pigment deposited in pulmonary macrophages and hilar lymph nodes from inhaled soot/coal dust. Generally benign in urban dwellers; pathologic in coal workers' pneumoconiosis.
Detail
Anthracosis represents accumulation of inhaled carbon particles within alveolar macrophages ('dust cells') that migrate to and aggregate in peribronchial and hilar lymph nodes, producing black streaks visible on gross lung section. It is essentially universal in adult urban smokers and coal miners and is itself harmless. Massive carbon load in coal miners can progress to simple coal workers' pneumoconiosis (upper-lobe macules/nodules) or, in some cases, progressive massive fibrosis (large black scars >2 cm). Caplan syndrome = pneumoconiosis + rheumatoid arthritis with intrapulmonary nodules. Anthracotic pigment is distinguished from hemosiderin by its black color and lack of iron stain positivity.
Sources
- Robbins Basic Pathology 10th ed
- First Aid for USMLE Step 1 2024
- Pathoma
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