Chronic myelomonocytic leukemia developed 7 years after the onset of idiopathic thrombocytopenic purpura like syndrome

A 55-year old woman admitted to our hospital with bleeding tendency. She was diagnosed as having idiopathic thrombocytopenic purpura (ITP) by the platelet count 4.8 x 10(4)/microliter, Platelet associated IgG (PAIgG) 88.5 ng/10(7) cells, and an increase of megakaryocyte (81/microliter) of the sternal bone marrow. No obvious dysplasia of three lineages was observed. Because she did not respond to corticosteroid and gamma globulin, she was undertaken splenectomy 3 years after the diagnosis and the platelet count had been kept more than 3.0 x 10(4)/microliter during the following 2 years. After 7 years from the onset of ITP, she was admitted because of leukocytosis (16500 microliters with 8% monocytes) and thrombocytopenia (1.9 x 10(4)/microliter) with bleeding tendency. Hypercellular bone marrow with dysplasia of three lineages such as dyserythropoiesis, Pelger like nucleus, and micromegakaryocyte was observed. The chromosomal analysis presented 46XX, del (20) (q11.2) in all (50/50) cells. She was diagnosed as having chronic myelomonocytic leukemia (CMMoL). This is a difficult case in which it was distinguish ITP from refractory thrombocytopenia, a subtype of myelodysplastic syndrome. We reexamined and found some morphological abnormalities at diagnosis, suggesting that it might be preleukemic stage.