Conclusions

This case describes a young adult diagnosed with BCR::ABL1-positive chronic-phase chronic myeloid leukemia at 24 years of age harboring a rare three-way variant Philadelphia chromosome translocation, t(6;9;22)(p21;q34;q11.2). Despite a nine-year disease course characterized by marked leukocytosis, massive splenomegaly, persistent BCR::ABL1 positivity, and moderate marrow fibrosis, repeat evaluation demonstrated persistent chronic-phase disease without evidence of accelerated-phase or blast-phase transformation. This case highlights the clinical heterogeneity of CML and illustrates that significant disease burden does not necessarily correlate with disease progression. Furthermore, it contributes to the limited literature describing chromosome 6-associated variant Philadelphia chromosome translocations and their long-term clinical behavior. Continued molecular monitoring, cytogenetic assessment, and adherence to tyrosine kinase inhibitor therapy remain essential for optimizing long-term outcomes in young patients with persistent CML.