Management of chronic myeloid leukemia presenting with isolated thrombocytosis and complex Philadelphia chromosome

Rationale: Chronic myelogenous leukemia (CML) with thrombocytosis and complex chromosomal translocation is extremely rare in clinical setting. Here, we reported the clinical and pathological characteristics of CML patients, which were characterized by thrombocytosis and complex Philadelphia chromosome translocation. Moreover, we also introduced our therapeutic schedule for this patient as well as review relative literature. Patient concerns: A 24-year-old female presented with night sweating, fatigue, and intermittent fever for 1 month. Diagnosis: Fluorescence in situ hybridization results revealed that breakpoint cluster region (BCR)-Abelson (ABL) gene fusion in 62% of the cells and karyotyping showed a complex 3-way 46, XY, t(9;22;11) (q34;q11;q13) [19/20] translocation. This patient was diagnosed with CML complicated with thrombocytosis and complex Philadelphia chromosome translocation. Interventions: The patients received continuously oral imatinib mesylate tablets (400 mg) once a day. Outcomes: After treatment with imatinib for 3 months, the BCR/ABL IS was less than 0.1% and achieved major molecular response. Moreover, the BCR/ABL IS of this patient achieved major molecular response. The BCR/ABL IS values at 6 months and 12 months were less than 0.01% and 0.0032%, respectively. And no BCR/ABL fusion was detected in the next 2 years follow-up period. Lessons: Imatinib might represent a preferred therapeutic option for CML patients with rare thrombocytosis and complex chromosomal translocation. In addition, BCR/ABL fusion gene examination in patients with thrombocytosis might represent an effective strategy to avoid the misdiagnosis of this specific CML population.