Burkitt leukemia with precursor B-cell features that developed after ruxolitinib treatment in a patient with hydroxyurea-refractory JAK2V617F-myeloproliferative neoplasm

• Published in: Journal of Clinical and Experimental Hematopathology 2021, Vol.61(2), pp.114-119
• Main Authors: Fukutsuka, Katsuhiro, Iioka, Futoshi, Maekawa, Fumiyo, Nakagawa, Miho, Kishimori, Chiyuki, Hayashida, Masahiko, Tagawa, Shunsuke, Akasaka, Takashi, Honjo, Gen, Ohno, Hitoshi
• Format: Article
• Language: English
• Subjects: Case Report; JAK2V617F mutation; myeloproliferative neoplasm; precursor B-cell Burkitt leukemia; ruxolitinib; t(8; 14)(q24; q32)/MYC-IGH
• ISSN: 1346-4280; 1880-9952
• DOI: 10.3960/jslrt.21001

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.