Lung biopsy showing interstitial accented chronic inflammation and anthracotic pigment containing fine birefringent material. A: Overview, HE staining. Scale bar = 200 μm, enlarged area highlighted (black box). B: Enlargement of A showing the anthracotic pigment and surrounding reactive tissue, scale bar = 50 μm. C: Same area as B illuminated by polarised light: Bright deposits of birefringent materials and dimly glowing collagen fibers.
Scheel et al. Diagnostic Pathology 2012 7:26 doi:10.1186/1746-1596-7-26