Fig. 6

Patient 3. Histological sample, lung biopsy a Surgical lung biopsy showing marked accumulation of pigmented alveolar macrophages with scattered small lymphoid aggregates (H&E × 100). b Alveolar macrophages with coarse golden-brown cytoplasmic pigment. There is reactive type 2 hyperplasia and mild expansion of alveolar walls with scattered small lymphocytes and minimal fibrosis, but no features of capillaritis or vasculitis are seen (H&E × 200). c The cytoplasmic pigment is positive with Perls Prussian Blue stain confirming it to be haemosiderin. Note also iron encrustation of elastin fibres in small vessels (Perls Prussian Blue stain × 200)