Immunophenotyping in chronic B-cell neoplasms has permitted more precise characterization of the neoplastic cells, leading to the recognition of well defined disease entities. Immunological markers play a key diagnostic role by establishing clonality in B-cell disorders, thus, distinguishing between neoplastic and reactive B lymphocytosis. Immunophenotyping can be carried out either by flow cytometry done on bone marrow aspirates or by immunohistochemical methods on fixed cells spread on slides. Diagnosis of a B-cell lymphoma requires first the identification of a neoplastic B-cell population...