Atypical presentation of chronic myeloid leukemia as extreme thrombocytosis

Abstract

Chronic myeloid leukemia (CML) is a type of myeloproliferative neoplasm which typically presents with leukocytosis but rarely presents with extreme thrombocytosis with no/mild increase in leukocytes. Here, we describe a unique case of 42-year-old female with peripheral blood smear features that were favoring essential thrombocythemia (ET). However, further studies such as bone marrow and cytogenetic study were suggestive of CML in chronic phase. In some cases, CML mimics ET and cytogenetic study is the confirmatory test. ET and CML have different therapeutics and prognosis, and it is always necessary to consider CML as a differential diagnosis in cases of isolated thrombocytosis/extreme thrombocytosis cases.