Acute leukemias are diseases of unknown origin that are characterized by the uncontrolled proliferation of a certain type of immature hematopoiesis cells. These cells invade the bone marrow, displacing normal cells and, progressively, the rest of the body. The acute term defines both the rapid rate of instauration of these leukemias and the immaturity of proliferating cells, facts that differentiate them from chronic leukemias in which the instability is slower and overlapping and the proliferating cells much more mature.

On the basis of their cytological characteristics, affected populations, treatment and prognosis, we classically distinguish four large groups of acute leukemias: