Image Description
Bone marrow examination is not necessary for the diagnosis of CLL. However, it may offer useful information regarding the status of hematopoiesis. Lymphocytes make up more than 30% of all cells in the bone marrow aspirate smears. Their morphology is similar to that of circulating leukemic cells. The bone marrow core biopsies show different patterns of infiltration: a) diffuse, solid lesions which appear dark on low magnification; the least common pattern, b) focal, non-paratrabecular nodules, and c) interstitial pattern in which the CLL cells are admixed with other hematopoietic elements. Proliferation foci and true germinal centers are extremely rare. Extensive solid, diffuse infiltration of the bone marrow is associated with cytopenias, advanced clinical stage, and has been linked with the presence of 70-kDa zeta-associated protein (ZAP-70). The image shows high magnification of a bone marrow aspirate smear. The predominant cell population is small, dark typical cells of CLL with scanty cytoplasm and condensed nuclear chromatin. Occasional megakaryocytes are also present.
About the Disease
B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) are the most common mature B-cell neoplasms and considered to be different manifestations of the same disease. CLL: It is the most common mature B-cell leukemia in the Western hemisphere and makes up 30% of all leukemias. It mainly affects middle-aged and elderly patients with a male predominance. The neoplastic cells are predominantly in blood and bone marrow. CLL is asymptomatic in most patients and often detected incidentally on complete blood counts. The diagnosis requires absolute mature lymphocytosis of ≥ 5.0 x 109/L sustained for at least 3 months. Immunophenotype: Multicolor flow cytometry shows the following results in a typical case: mature B-cell phenotype with weak monotypic surface immunoglobulin, CD5 coexpression, weak CD20, weak CD22, CD23, CD19, weak CD11c; negative for CD10, FMC7, and CD79b. SLL: In contrast to CLL, SLL is much less common, making up only about 4% of non-Hodgkin lymphomas. The distribution of the neoplastic cells in SLL is mainly extramedullary with very few leukemic cells in blood. The patients are often asymptomatic but may present with lymphadenopathy and splenomegaly.