Longitudinal bone marrow chromosome studies in potential leukemic myeloid disorders

The purpose of this study was to answer two questions: 1. Are patients with potentially leukemic myeloid disorders who develop leukemia necessarily preceded by marrow chromosome abnormalities? and 2. Do all that have such abnormalities develop acute leukemia? Direct bone marrow chromosome studies were performed in 18 patients with pancytopenia and in 10 with several unusual myeloproliferative disorders. The former have been followed between 6 months and 13 years; all had normal karyotypes and no evidence of leukemia. In the miscellaneous group, follow-up has varied between 6 months and 5 years, six patients had assorted chromosome abnormalities, including two with a clonal evolution. Three have died without evidence of leukemia, one has developed a questionable form of chronic eosinophilic leukemia and two are alive without leukemic transformation. It is concluded that the presence of bone marrow chromosome abnormalities in such patients does not necessarily mean that transformation to acute leukemia is imminent.