Very Rare Coexistence of Inversion (16), Trisomy 8, and t(9;22) in a Chronic Myeloid Leukemia Patient Progressing to Myeloblastic Crisis.

Objectives: Chronic myeloid leukemia (CML) is typically characterized by the presence of the BCR-ABL1 fusion gene on chomosome 22 resulting from a t(9;22)(q34;q11.2) translocation. We report a case of a 59-year-old female with CML in the chronic phase, initially presenting with thrombocytosis and diagnosed with t(9;22) via conventional karyotyping and fluorescence in situ hybridization (FISH). Nine years and seven months after the initial diagnosis, despite treatment with standard imatinib mesylate therapy (400 mg daily), conventional cytogenetic analysis revealed the emergence of trisomy 8 and a pericentric inversion of chromosome 16 (inv(16) (p13q22)) in cells that already carried the t(9;22). Bone marrow aspiration and biopsy showed 80% blasts, predominantly expressing myeloid markers CD13, CD33, CD117, along with HLA-DR and CD34. Both FISH and conventional karyotyping confirmed the presence of trisomy 8, inversion of chromosome 16, and t(9;22). Additionally, reverse transcription-polymerase chain reaction (RT-PCR) confirmed the presence of the BCR-ABL fusion gene. The coexistence of these genetic abnormalities is often associated with an aggressive clinical course, rapid disease progression, and chemotherapy resistance. Following disease progression, the patient was treated with a combination of hydroxyurea (500 mg) and decitabine (50 mg), and her tyrosine kinase inhibitor (TKI) therapy was switched to bosutinib (400 mg). Despite these interventions, she developed pleural effusions and lung metastases and ultimately passed away approximately seven months after initiating the new treatment due to relapsed disease and infectious complications.