Abstract
Chronic myeloid leukemia with extreme thrombocytosis (CML-T), defined by a platelet count >1,000x10(9)/l is a rare leukemia subtype. The present case report described a 66-year-old female CML-T patient presenting with a platelet count of 3,798x10(9)/l, but a consistently normal spleen size. Following treatment with imatinib combined with interferon-α, the patient achieved hematological remission within 2 months, with a platelet count reduction to 311x10(9)/l and complete cytogenetic remission after 10 months. The patient experienced myocardial infarction and liver injury during treatment, which was managed with supportive care. The present case suggested that imatinib combined with interferon-α may be a safe and effective treatment option for patients with CML-T and extreme thrombocytosis and suboptimal response to imatinib monotherapy.