Image Description
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.
About the Disease
Hairy Cell Leukemia (HCL) is a mature B-cell neoplasm that mainly involves the blood, bone marrow, and splenic red pulp. It makes up only about 2% of all leukemias and predominantly affects middle-aged men (M:F = 4:1).The clinical features are often related to cytopenias and include recurrent infections (due to neutropenia) and weakness and fatigue (due to anemia). Monocytopenia is one of most sensitive markers of HCL. Splenomegaly is seen in 80% to 90% of cases; lymphadenopathy is uncommon. A small proportion of patients show polyclonal hypergammaglobulinemia. In about one-fourth of the patients, HCL is diagnosed incidentally.The neoplastic lymphocytes have an ill-defined, ruffled cytoplasmic border with hair-like surface projections. They express B-cell associated antigens CD19, CD20, and CD22. In addition, they are positive for CD103, CD25, and CD11c.