After hemorrhage, RBCs leave to the ECF releasing their hemoglobin
Then comes the macrophage phagocytosing them and transforming hemoglobin Iron to hemosiderin giving a brown pigment.
The causes that I can come up with now:
of course any Iron overload situation [hemachromatosis]
Brown tumors seen in bones in hyperparathyroidism
Heart failure cells seen in pulmonary edema
Don't forget that you need "Prussian Blue" stain to see these hemosiderin-laden macrophages.