Pulmonary congestion with dilated capillaries and leakage of blood into alveolar spaces leads to an increase in hemosiderin-laden macrophages, as seen here.

• 肺淤血时肺毛细血管扩张、管壁透性增加红细胞漏出进入肺泡腔，导致吞噬细胞内含铁血黄素颗粒增加，象图显示。