1. Division of Hematopathology, Tohoku University Hospital, Sendai, Japan;
2. Department of Hematology and Rheumatology, Tohoku University Graduate School of Medicine, Sendai, Japan;
3. Department of Pathology, Tohoku University Hospital, Sendai, Japan;
4. Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan