Acute nonlymphocytic leukemia (AML)

Alternative names:

acute granulocytic leukemia; acute myeloblastic leukemia; acute myelogenous leukemia; myeloid leukemia; splenomedullary leukemia; splenomyelogenous leukemia

Definition:

A malignancy of blood-forming tissues characterized by the proliferation of immature white blood cells called granular leukocytes.

Causes, incidence, and risk factors:

AML may occur at any age, but it primarily occurs in adults and in children below 1 year old. In acute leukemia, the malignant cell loses its ability to mature and specialize (differentiate) its function. These cells multiply rapidly and replace the normal cells. Bone marrow failure occurs as malignant cells replace normal bone marrow elements. The person becomes susceptible to bleeding and infection as the blood cells lose their ability to function.

Most cases seem to have no apparent cause. However, radiation, some toxins such as benzene, and some chemotherapy agents are thought to cause leukemia. Abnormalities in chromosomes may also play a role in the development of acute leukemia. Risk factors include exposure to radiation and chemicals, immunosuppression following organ transplantation, and blood disorders such as polycythemia vera, essential thrombocytopenia, and refractory anemia. The incidence is 1 out of 10,000 people.