Journal of Case Reports in Medicine,2013,2,1,1-2.Published:April 2013Type:Case ReportAuthors:Yoshinobu Saito, Naoto Takahashi, Hideaki Ohyagi, Yoshinori Shinohara, Masaaki Kume, and Kenichi Sawada Author(s) affiliations:Yoshinobu Saito,1 Naoto Takahashi,2 Hideaki Ohyagi,1,2 Yoshinori Shinohara,1,2 Masaaki Kume,1 and Kenichi Sawada2 1Department of Hematology, Hiraka General Hospital, 3-1, Maego Aza Yatsuguchi, Yokote City, 013-8610, JAPAN. 2Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City, 010-8543, JAPAN. Abstract:Transformation to acute myeloid leukemia (AML) frequently occurs in patients with myelodysplastic syndrome (MDS), and genetic evolution probably plays a critical role in this transformation. However, late appearance of the Philadelphia (Ph) chromosome during the course of transformed MDS is extremely rare. We report a 77-year-old man with transformed MDS and an acquired Ph chromosome. He was initially diagnosed with refractory anemia with 45,XY,del(5)(q?),-7,-14,-17,+mar1,+mar2 [7/20] as the major clone. After 4 months, hematological studies showed progression of anemia with increased number of blast cells. Conventional chromosome analysis revealed 45,XY,del(5)(q?),-7, t(9;22)(q34;q11.2),-14,-17,+mar1,+mar2 [20/20], a subclone with an acquired Ph chromosome derived from a stem clone observed at MDS diagnosis. RT-PCR results were positive for major BCRABL transcript. Although a comparison of whole-genome sequences between original and transformed clones would be informative, the acquired Ph chromosome probably played a role as a “class-I mutation,” which increases cell proliferation in transformed MDS. Keywords:Philadelphia chromosome; Myelodysplastic syndrome; Acute myeloid leukemiaView:PDF (582.63 KB) PDF Images Figure 1: Bone marrow morphology and G-banding revealed clonal evolution. (a) Bone marrow smear (Wright- Giemsa, 1,000×) showed MDS at diagnosis. (b) Karyotype at MDS diagnosis was 46,XY,del(5)(q?)[1]/45,XY,idem, -7,-14,-17,+mar1,+mar2[7]/45,XY,-5[4]/46,XY[8]. A major abnormal clone is shown in Figure 1(b). (c) Bone marrow smear (Wright-Giemsa, 1,000×) showed AML with multilineage dysplasia upon progression of anemia 4 months after MDS diagnosis. The size of the blast cells ranged from medium to large; they showed a high nuclear:cytoplasmic ratio and visible nucleoli. (d) Karyotypes at diagnosis of transformation to AML was 45,XY,del(5)(q?),-7,t(9;22)(q34;q11.2),-14,-17, +mar1,mar2[20]. The Philadelphia chromosome is marked by an arrowhead.