Figure 4. Microscopic features of PLCH. Intermediate-power photomicrograph (original magnification, x480; H-E stain) of a nodular lesion shows infiltrates composed of variable numbers of LCH cells (arrow), eosinophils (arrowhead), lymphocytes, fibroblasts, plasma cells, neutrophils, and pigmented cells. The latter are smoker’s macrophages derived from smoker’s bronchiolitis.