A Rare Sequential Occurrence of Chronic Lymphocytic Leukemia Following Chronic Myeloid Leukemia

Abstract

The association of chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) in the same patient is very rare. There are a few reports in the literature of such cases, the majority of which correspond to CML occurring during theevolutive course of CLL. We report a patient who developed CLL 18 months after he was diagnosed to be suffering from CML. There is only one other report of such a sequence occurring in the same patient. The case is discussed with reference to the literature. Case ReportA 57-year-old man presented to our institution with an abdominal mass. He had splenomegaly of 15 cm. His total WBC count was 72x10 9 /L, with a differential count of blasts 1%, promyelocytes 2%, myelocytes 9%, metamyelocytes 5%, band forms 4%, polymorphs 64%, lymphocytes 4%, eosinophils 3%, and basophils 6%. His hematocrit was 46% and platelet count was 560x10 9 /L. The leukocyte alkaline phosphatase score was 12 (N 85-95). Bone marrow aspiration and biopsy showed myeloid and megakaryocytic hyperplasia. Cytogenetic analysis of the bone marrow revealed 46,XY,t(9;22)(q34;q11), the Philadelphia (Ph) chromosome being observed in all the 25 metaphases. A diagnosis of CML in chronic phase was made, and therapy with hydroxyurea was instituted. His counts gradually fell, and was maintained between 13 to 15xl0 9 /L. Eighteen months after the initial diagnosis, there was an increase in counts to 24x10 9 /L, with a significant lymphocytosis. Bone marrow aspiration was done at this juncture. The smears showed sheets of lymphocytes, whose morphology appeared to be mature (Figure la &lb). Immunophenotyping by flow cytometry was consistent with a diagnosis of CLL (CD5+, Cd19+, CD20+, CD 23+, Tdt-). Cytogenetic analysis of the bone marrow showed apersistence of the Ph chromosome and the presence of an additional anomaly: isochromosome (17)(q10) in 25% of the metaphases. The karyotype was interpreted as 6,XY,t(9;22)(q34;q11)[24]/46,XY,t(9;22)(q34;q11),i(17) (q10) [8]. The patient has been under observation for the past three months, and peripheral smears done at fortnightly intervals show significant lymphocytosis, with an occasional myelocyte, metamyelocyte and basophil.