Journal of Clinical and Experimental Hematopathology
Online ISSN : 1880-9952
Print ISSN : 1346-4280
ISSN-L : 1346-4280
Case report
Burkitt leukemia with precursor B-cell features that developed after ruxolitinib treatment in a patient with hydroxyurea-refractory JAK2V617F-myeloproliferative neoplasm
Katsuhiro FukutsukaFutoshi IiokaFumiyo MaekawaMiho NakagawaChiyuki KishimoriMasahiko HayashidaShunsuke TagawaTakashi AkasakaGen HonjoHitoshi Ohno
ジャーナル オープンアクセス

2021 年 61 巻 2 号 p. 114-119


A 62-year-old woman, who had a 16-year history of JAK2V617F-mutated myeloproliferative neoplasm (MPN), developed Burkitt leukemia (BL) 16 months after treatment with ruxolitinib to control hydroxyurea-refractory conditions. BL cells were CD10+, CD19+, CD20, CD34, cytoplasmic CD79a+, and TdT+, and lacked surface immunoglobulins but expressed the cytoplasmic μ heavy chain. In the bone marrow, nuclear MYC+ BL cells displaced the MPN tissues. t(8;14)(q24;q32) occurred at a CG dinucleotide within MYC exon 1 and at the IGHJ3 segment, and an N-like segment was inserted at the junction. The V-D-J sequence of the non-translocated IGH allele had the unmutated configuration. DNA from peripheral blood at a time of the course of MPN exhibited homozygous JAK2V617F mutation, while that at BL development included both JAK2V617F and wild-type DNAs. Although the association between JAK1/2 inhibitor therapy for MPN and secondary development of aggressive B-cell neoplasm remains controversial, this report suggests that, in selected patients, close monitoring of clonal B-cells in the BM is required before and during treatment with JAK1/2 inhibitors.

© 2021 by The Japanese Society for Lymphoreticular Tissue Research

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