Diagnostic pathway for the investigation of thrombocytosis

摘要

Chronic myeloid leukaemia (CML) may present with an isolated thrombocytosis and thus mimic essential thrombo-cythaemia (ET). The diagnostic criteria for ET proposed within the British Committee for Standards in Haematology guidelines (Harrison et al, 2010) are listed in Table I. Here, A3 requires exclusion of CML, usually by demonstrating the absence of a BCR-ABL1 fusion gene or transcript in samples from bone marrow or peripheral blood. However the text of the guideline indicated that BCR-ABL1 testing could be restricted to patients with atypical features, such as baso-philia, left shift of neutrophils or the presence of small hypolobated megakaryocytes. Such features are easily overlooked and missing a diagnosis of CML has major consequences for the patient.