Haemosiderin-laden macrophages aka heart failure cells
Heart failure cells are characteristic of well, heart failure. Left heart failure results in the damming up of blood in the pulmonary veins, increasing pressure in it, and thusly pressure in the lung capillaries increase too. Capillary leakiness leads to an accumulation of erythrocytes in the interstitium, where they are phagocytosed by macrophages and eventually become heart failure cells. 

Haemosiderin-laden macrophages aka heart failure cells

Heart failure cells are characteristic of well, heart failure. Left heart failure results in the damming up of blood in the pulmonary veins, increasing pressure in it, and thusly pressure in the lung capillaries increase too. Capillary leakiness leads to an accumulation of erythrocytes in the interstitium, where they are phagocytosed by macrophages and eventually become heart failure cells.