Morphological and Immunophenotypic Clues to the WHO Categories of Acute Myeloid Leukaemia

Diagnosis and classification of acute myeloid leukaemia (AML) require cytogenetic and molecular genetic investigation. However, while these evaluations are pending, morphology supplemented by immunophenotyping can provide clues to the diagnosis of specific cytogenetic/genetic categories of AML. Most importantly, acute promyelocytic leukaemia can be diagnosed with a high degree of certainty. However, provisional identification of cases associated with t(8; 21), inv(16), t(1; 22), and <i>NPM1</i> mutation may also be possible. In addition, transient abnormal myelopoiesis of Down’s syndrome can generally be diagnosed morphologically.