Nine Years of Chronic Myeloid Leukemia in a Young Adult With a Variant Philadelphia Chromosome: A Case Report and Brief Literature Review.

We report the case of a man diagnosed with chronic-phase chronic myeloid leukemia (CML) at 24 years of age after marked leukocytosis was incidentally identified during routine blood donation screening. Initial evaluation demonstrated a white blood cell count of 187.8 ×10³/µL, anemia, basophilia, and left-shifted myeloid proliferation. Bone marrow examination confirmed chronic-phase CML, and cytogenetic analysis identified a rare variant Philadelphia chromosome translocation, t(6;9;22)(q34;q11.2;p21). Fluorescence in situ hybridization confirmed BCR::ABL1 rearrangement in 94.5% of analyzed cells. Nine years after diagnosis, the patient was hospitalized for evaluation of persistent disease. Repeat bone marrow examination demonstrated markedly hypercellular marrow (95% cellularity) with myeloid hyperplasia, decreased erythropoiesis, and moderate reticulin fibrosis (MF-2), without evidence of accelerated-phase or blast-phase transformation. Peripheral blood flow cytometry identified a small CD34-positive immature myeloid population (3.8-4.3% of leukocytes) without immunophenotypic evidence of acute leukemic transformation. Computed tomography revealed massive splenomegaly measuring 31.9 cm with associated mass effect on adjacent abdominal structures. This case illustrates the long-term clinical course of chronic-phase CML in a young adult with a rare variant Philadelphia chromosome translocation. Despite persistent hematologic abnormalities, marked splenomegaly, and moderate marrow fibrosis nearly a decade after diagnosis, the patient remained in chronic phase without leukemic transformation. The case highlights the importance of comprehensive cytogenetic evaluation, accurate disease-phase assessment, and long-term molecular surveillance in patients with uncommon cytogenetic variants.