Secondary Ph-positive CML with a minority monosomy 7 clone.

We report a case of Ph-positive chronic myelogenous leukemia (CML) secondary to previous treatment for a lymphoma. At the time of original diagnosis of lymphoblastic lymphoma, chromosome studies of blood and bone marrow were normal. Following therapy and a clinical remission complicated by CNS relapse, the patient presented 16 months after treatment was discontinued with a WBC of 110,000 mm-3, consistent with CML. Blood and marrow cytogenetic studies at this time showed a Ph chromosome, t(9;22)(q34;q11) translocation, without other karyotypic alteration. A separate small clone with the karyotype 45,XY, -7 was found in the blood. His disease followed an aggressive course and he died 3 months later. The autopsy findings indicated CML in blast crisis. Molecular studies performed on cells replacing a lymph node revealed a rearrangement of the breakpoint cluster region (bcr) of chromosome #22 and of the immunoglobulin heavy chain locus. Taken together, it seems most likely that the patient's CML developed as a second neoplasm following successful elimination of his lymphoblastic lymphoma by therapy.