Hairy Cell Leukemia : Spleen
Spleen is almost always involved in hairy cell leukemia resulting in massive splenomemgaly. This intermediate magnification view shows numerous small areas of hemorrhage (blood lakes or pseudosinuses) that are lined by hairy cells. The white pulp areas are inconspicuous. The blood lakes are not specific for HCL and result from damage to the endothelial cells caused by interaction with hairy cells. At higher magnification, the hairy cells are monotonous with oval nuclei and abundant clear cytoplasm creating a fried-egg appearance.