Acute myelomonocytic leukaemia

**Definition:** An acute leukaemia characterised by the proliferation of both neutrophil and monocyte precursors.

**Long definition:** Acute myeloblastic leukemia (AML) (see this term) is a group of malignant bone marrow neoplasms of myeloid precursors of white blood cells. Acute myelomonocytic leukemia (AML-M4) is a common type of pediatric AML. However, the condition is rare and represents approximately 3 % of all leukemias during childhood and has an incidence of 1.1-1.7 per million per year. The symptoms may be aspecific: asthenia, pallor, fever, dizziness and respiratory symptoms. More specific symptoms are bruises and/or (excessive) bleeding, coagulation disorders (DIC), neurological disorders and gingival hyperplasia. Diagnostic methods include blood analysis, bone marrow aspirate for cytochemical, immunological and cytogenetical analysis, and cerebrospinal fluid (CSF) investigations. A characteristic chromosomal abnormality observed in AML-M4 is inv(16). Treatment includes intensive multidrug chemotherapy and in selected cases allogeneic bone marrow transplantation. Nevertheless, outcome of AML remains poor with an overall survival of 35-60%. Children with AML-M4 carrying the inv(16) abnormality have a better prognosis (61% 5-year overall survival). New therapeutics are required to increase the probability of cure in this serious disorder.