Acute myelomonocytic leukemia (AML-M4) is a form of acute myeloid leukemia (AML; see this term) that usually presents with fever, pallor, dyspnoea, fatigue, loss of weight and bleeding disorders. Leukemia cutis and gingival infiltration can also be seen. AML-M4 may in some cases be associated with abnormal bone marrow eosinophilia (AML-M4Eo) and/or with inv (16) which is associated with a high response rate to chemotherapy and favorable clinical outcome compared to other types of AML. Intracranial masses can occur, usually in the setting of AML-M4Eo with inv (16).