CD5 PLUS CHRONIC B-CELL LEUKEMIA WITH FEATURES INTERMEDIATE TO CHRONIC LYMPHOCYTIC-LEUKEMIA AND HAIRY-CELL LEUKEMIA

Chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL) are d ifferentiated B-cell leukemias with well-described clinical, morpholog ic, and immunologic characteristics. We encountered two patients with indolent chronic B-cell leukemia showing overlapping features of these malignancies. The patients had progressive splenomegaly, minimal lymp hadenopathy, and abnormal lymphoid cells with abundant cytoplasm and v illi, which were strongly positive for surface antigens CD22 and CD11c , features associated with HCL. However, blood counts showed lymphocyt osis without neutropenia and monocytopenia, and the bone marrow biopsi es demonstrated tightly aggregated nodules of lymphocytes. In addition , the lymphoid cells were dual positive for CD19 and CD5, displaying w eak-to-moderately positive monoclonal surface immunoglobulin, findings strongly suggestive of CLL. One patient failed to respond to therapy with chlorambucil and prednisone. The second patient showed a partial response to treatment with 2-chlorodeoxyadenosine. We compare our pati ents with similar variants of differentiated B-cell leukemias reported in the literature, including disorders described as hairy cell varian t (HCL-V) or splenic lymphoma with villous lymphocytes (SLVL).