times 109/l and hemoglobin 111 g/l. Bone marrow examination revealed an unclassifiable chronic myeloproliferative disorder. The patient received symptomatic therapy. She was readmitted 1 year later with a pancoast tumor and inguinal lymph node enlargement. Laboratory analysis revealed a leukocytosis of 25.6 times 109/l with 2% blasts and myeloid precursors, hemoglobin 80 g/l and normal platelet count. Bone marrow aspirate and biopsy were hypercellular with abnormal megakaryocytes, an increased number of eosinophils and 10% blasts. Histology of the lymph node was consistent with myeloid sarcoma. The white cell count increased rapidly up to 114.4 times 109/L, with 17% blasts and severe thrombopenia. The patient was treated with low-dose Ara-C, achieved a partial hematological response but developed an ileus and died few days later. No autopsy was performed.
Cytogenetic analysis of bone marrow cells performed at diagnosis revealed a t(5;9)(q13;q34) as the sole chromosomal abnormality. The constitutional karyotype was normal. RT-PCR for BCR/ABL was negative. Cytogenetic follow-up on bone marrow cells 11 months later revealed the presence of three abnormal clones, all characterized by the presence of t(5;9) and add(17)(q2?1). Additional abnormalities included del(5)(q13;q34) in clone 1, an additional rearrangement involving der(9) in 9q34 in clone 2 and hyperdiploidy (+8, +11, +12, +18 and +19) in clone 3 (Figure 1).
We conclude that broad molecular screening allowed to reveal a genetically distinct entity with poor prognosis, heterogenous morphological and clinical manifestation, but with evident option of a targeted therapy. Broad molecular screening should be an integral part of diagnostics for all types of leukemias. It may detect rare diseases, provide prognostic criteria and clarify therapeutic options early on.