NCIt definition : A neoplasm of small B-lymphocytes with hairy projections in bone marrow, spleen, and
peripheral blood. Most patients present with splenomegaly and pancytopenia. (WHO,
2001);
Alternative definition : NCI-GLOSS: A rare type of leukemia in which abnormal B-lymphocytes (a type of white
blood cell) are present in the bone marrow, spleen, and peripheral blood. When viewed
under a microscope, these cells appear to be covered with tiny hair-like projections.;