[Refractory anemia with excess of blasts (RAEB) with a high level of HbF that preceded apparent pancytopenia].

A 76-year-old male was kept under observation for idiopathic interstitial peumonitis in our hospital from August 1992. Laboratory data revealed a slightly high level of HbF (2.7%) but normal values of other hematological examination. The level of HbF increased slowly, and in April 1994, pancytopenia appeared for the first time. Bone marrow was normocellular with myelodysplasia and 9% blasts. Cytogenetic analysis revealed 46, XY, del (20) (q11;q13). He was diagnosed as having myelodysplastic syndrome (MDS), refractory anemia with excess of blasts. At diagnosis of MDS, the level of HbF was 20.0%. He developed acute myelocytic leukemia 3 months later. It has been reported that approximately 40% of patients with MDS have higher HbF levels than normal, which is considered to be functional abnormality of the MDS clone. It is suggested that the MDS clone had already increased in this patient at presentation, 32 months before pancytopenia appeared.