Acute nonlymphocytic leukemia (ANLL) with isochromosome i(17q) as the sole chromosomal anomaly: a distinct entity?

3 patients with acute nonlymphocytic leukemia (ANLL) and an isochromosome (17q) as the sole chromosomal defect are reported. Besides this cytogenetic pattern, they shared several clinical and hematological features such as male sex, advanced age, spleno- and/or hepatomegaly and a suspected preceding myeloproliferative syndrome. Bone marrow cytology was characterized by hypercellularity, prominent baso- and eosinophilia, decreased erythropoiesis and marked increase of dysmorphic megakaryocytes. We suggest that some or most patients with ANLL and i(17q) as the sole cytogenetic defect represent blastic transformation of an underlying chronic myeloproliferative disorder rather than de novo ANLL.