A case mimicking chronic myeloid leukemia with t(8;22)(p11;q11)/BCR-FGFR1 and sequential transformation to B-acute lymphoblastic leukemia and acute myeloid leukemia

Myeloid/lymphoid neoplasm is a rare malignancy with an aggressive course and rapid transformation to acute myeloid leukemia (AML), or less frequently to acute lymphoblastic leukemia (ALL). Cases with t(8;22)(p11;q11) BCR-FGFR1 fusion gene may be misdiagnosed with chronic myeloid leukemia (CML), due to a very similar morphologic and clinical profile. We report a case of 48-year-old woman who complained of weakness and gastric pain. She had splenomegaly, eosinophilia, and elevated white blood cells. Bone marrow (BM) aspiration biopsy was performed with an initial diagnosis of CML. Cytogenetic analysis of the BM showed a 46,XX,t(8;22)(p11.2;q11.2). She was diagnosed with myeloid/lymphoid neoplasm with eosinophilia and rearrangement of FGFR1 gene. Throughout the chronic phase, the patient was treated with hydroxurea. Additional chromosomal abnormalities developed during therapy. Owing to the (8;22) clone, our patient did not respond to the treatment and rapidly transformed first to B-ALL and then AML. To the best of our knowledge, this is the first MPN patient with rearrangement of BCR and FGFR1 genes with rapid transformation to B-ALL and then to AML.