Therapy-related chronic myelomonocytic leukaemia with bone marrow eosinophilia associated with der(11)t(1;11)(q21;q14).

A 19-year-old male with chronic myelomonocytic leukaemia (CMML) with bone marrow eosinophilia terminating in myeloblastic transformation is described. Before the appearance of CMML, he received a total dose of 2,894 mg of nimustine for the treatment of a pontine glioma over 12 years. Peripheral blood count showed leucocytosis with mature neutrophils and monocytes. Bone marrow smears showed myeloid hyperplasia with increased blasts and abnormal eosinophils and dysplastic features in the myeloid and megakaryocytic cells. A karyotype analysis of the bone marrow cells indicated 46, XY, der(11)t(1;11)(q21;q14). No bcr/abl rearrangement was observed in the cells. He was treated with hydroxyurea to control the leucocyte count, but myeloblastic transformation developed.