Cytogenetic studies in patients with myelofibrosis and myeloid metaplasia

Serial cytogenetic studies were performed in 20 documented cases of myelofibrosis with myeloid metaplasia. Of those cases studied at the time of initial diagnosis, 64% were aneuploid while the overall incidence of aneuploidy was 75%. In six patients in this series, the disease terminated in leukemia; two of these patients had normal karyotypes, one had a normal karyotype initially and developed aneuploidy nearly three years later, and three had varying degrees of aneuploidy. Of the 14 cases who showed no evidence of leukemia, only three had completely normal karyotypes. These studies demonstrate that extensive chromosomal abnormalities of a complex and non-specific nature are common in myelofibrosis. The cytogenetic data reflect the relationship which exists between leukemia and the various myeloproliferative disorders, and also indicates a myelofibrosis should in fact be considered as an expression of another, underlying myeloproliferative disorder rather than as a separate disease. A change in karyotype may herald the appearance of a malignant clone and subsequent development of leukemia.