%0 Case Reports %T [De novo blast phase of chronic myeloid leukemia with 3q26 abnormality diagnosed by cytogenetic analysis of extramedullary lesion]. %A Matsunaga T %A Naganuma K %A Tabayashi T %A Kawada T %A Sakata N %A Takahashi Y %A Kimura Y %A Anan T %A Mitsuhashi T %A Kubota Y %A Sawada K %A Yamashita T %A Momose S %A Higashi M %A Tamaru JI %A Kizaki M %J Rinsho Ketsueki %V 63 %N 12 %D 2022 %M 36653137 暂无%R 10.11406/rinketsu.63.1643 %X A 62-year-old woman was presented at our hospital with visual disturbance. An ocular examination revealed bilateral Roth spots. Laboratory data revealed leukocytosis (236,200 µl) with an excess blast (11%). Physical examination and computed tomography (CT) showed systemic lymphadenopathy. A bone marrow examination revealed a composition of 9.2% blast. Chromosomal analysis on bone marrow cells revealed 46,XX,t (3;12)(q26.2;p13),t (9;22)(q34.1;q11.2) in 80% of metaphases (16/20). Inguinal lymph node biopsy revealed diffuse proliferation of myeloperoxidase (MPO)-positive abnormal cells. Fluorescence in situ hybridization analysis was used to detect the BCR-ABL1 fusion gene and split the signals of MECOM and ETV6. She was diagnosed with de-novo chronic myeloid leukemia (CML) extramedullary blast crisis. She received tyrosine kinase inhibitor (TKI) combination chemotherapy and allogeneic hematopoietic stem cell transplantation and achieved a major molecular response. In this study, we reported a case of CML in blast-phase initially presenting as extramedullary, in which cytogenetic and molecular analyses were useful in the staging method.