Philadelphia-positive acute lymphoblastic leukemia in a case of MPL p.(W515L) variant essential thrombocythemia: case report and literature review

Abstract

Acute lymphoblastic leukemia (ALL) arising in preexisting myeloproliferative neoplasms (MPN) is rare with historical cases unable to differentiate between concomitant malignancies or leukemic transformation. Here, we report a case of patient with Philadelphia positive B lymphoblastic leukemia (Ph+ALL) who developed from MPL-mutated essential thrombocythemia (ET) 13 years after initial presentation. Molecular studies showed the discrepancy between the high percentage of lymphocyte blasts (91%) and the low MPL p.(W515L) variant allele frequency (2.59%) at diagnosis in the bone marrow, indicating that the Ph+ALL clone did not originate from the ET clone carrying the MPL p.(W515L) variant. After the treatment of a new tyrosine kinase inhibitor flumatinib and prednisolone, cytogenetic and molecular remission had been achieved rapidly and followed by the recovery of original ET manifestation. Although relapsed eventually, this is still a very rare case of simultaneous presence of two cytogenetics abnormalities and evolution of MPL p.(W515L) variant ET to Ph+ALL and may provide evidence to illustrate the clonal relationship of MPN and post-MPN ALL.

Keywords:

• Acute lymphoblastic leukemia
• essential thrombocythemia
• MPL mutation
• philadelphia chromosome

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Funding

This work is supported in part by the National Natural Science Foundation of China [81770172 and 82070166], ”333 Project” of Jiangsu Province [BRA2019103], and Key Medical Subjects of Jiangsu Province [ZDXKB2016020].