The t(5;12)(q31not, vert, similar35;p12not, vert, similar13) is rare among cytogenetically categorized myeloid diseases. Here we describe a case of myelodysplastic syndrome (MDS) with basophilia followed by leukocytosis, basophilia, and eosinophilia with t(5;12)(q31;p13).A 44-year-old man was referred to Tsukuba University Hospital in August 2005, due to severe anemia and thrombocytopenia. Peripheral blood examination showed hemoglobin 4.5 g/dL, with mean corpuscular volume 109 fL, platelets 73 × 109/L, and white blood cells 4.9 × 109/L with 23% basophils, 3% eosinophils, and 0% blasts. Bone marrow was slightly hypocellular, with trilineage dysplasia. Cytogenetic examination of the bone marrow cells revealed a normal karyotype, 46,XY. A diagnosis of myelodysplastic syndrome–refractory anemia with excess blasts type 2 (MDS-RAEB2) was made according to the WHO classification
