Trisomy 4 and ring chromosome in a patient with acute myelomonocytic leukemia

We describe a patient with acute myelomonocytic leukemia (AMML) in whom cytogenetic analysis revealed trisomy 4 associated with a ring chromosome. In addition, in a cytogenetically unrelated clone, trisomy 8 and 5q- abnormalities were detectable. The possibility of a subclinical myelodysplastic syndrome preceding the onset of AML is discussed on the basis of the morphological and cytogenetic findings.