[A case of myelofibrosis that developed polycythemia vera following treatment with ranimustine and then acute myelogenous leukemia (M0)].

A 60-year-old Japanese woman was admitted to our hospital because of fatigue, weight loss and abdominal distension. Myelofibrosis was diagnosed, based on anemia, huge hepatosplenomegaly, leukoerythroblastosis and bone marrow fibrosis. Following treatment with ranimustine, anemia and splenomegaly improved. Seven months after initial therapy of ranimustine, however, polycythemia (RBC 7.39 x 10(6)/microliter; Hb 19.1 g/dl, Ht 65.9%) developed gradually, then RBC decreased to normal level following venesection (total 1,200 ml). After 32 months, blastic transformation occurred. The blasts were negative for myeloperoxidase. By flow cytometric analysis, the cells were positive for CD2, CD13, CD33 and HLA DR. Thus, AML (M0) was diagnosed. Despite of treatment with multicytotoxic agents, she died of DIC 36 months after the initial diagnosis of myelofibrosis. The progression from myelofibrosis to polycythemia is rare and only 15 cases have been reported so far. In addition, although a chromosomal abnormality, 46, XX, t(3; 12) (q25; p11), was present at the time of first diagnosis of myelofibrosis, the development of an additional abnormality, del(11) (q-), might be related to the transformation to AML.