Trisomy 21 as the sole clonal aberration in a patient with acute myelomonocytic leukemia with abnormal bone marrow eosinophils and extramedullary involvement.

We describe a 30-year-old acute myelomonocytic leukemia patient with abnormal bone marrow eosinophils (AML FAB subtype M4Eo) with extensive extramedullary involvement and, in the abscence of an aberration involving chromosome 16, clonal trisomy 21 in the leukemic blast cells.