Childhood acute myeloid leukemia (AML) is a cancer of the blood and bone marrow. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, and acute nonlymphocytic leukemia. Cancers that are acute usually get worse quickly if they are not treated. Cancers that are chronic usually get worse slowly.
Normally, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. A lymphoid stem cell becomes a white blood cell.
A myeloid stem cell becomes one of three types of mature blood cells:
In AML, the myeloid stem cells usually become a type of immature white blood cell called myeloblasts (or myeloid blasts). The myeloblasts, or leukemia cells, in AML are abnormal and do not become healthy white blood cells. The leukemia cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. The leukemia cells can spread outside the blood to other parts of the body, including the central nervous system (brain and spinal cord), skin, and gums. Sometimes leukemia cells form a solid tumor called a granulocytic sarcoma or chloroma.
There are subtypes of AML based on the type of blood cell that is affected. The treatment of AML is different when it is a subtype called acute promyelocytic leukemia (APL) or when the child has Down syndrome.
In chronic myelogenous leukemia (CML), too many bone marrow stem cells become a type of white blood cell called granulocytes. Some of these bone marrow stem cells never become mature white blood cells. These are called blasts. Over time, the granulocytes and blasts crowd out the red blood cells and platelets in the bone marrow. CML is rare in children.
Juvenile myelomonocytic leukemia (JMML) is a rare childhood cancer that occurs more often in children around the age of 2 years and is more common in boys. In JMML, too many bone marrow stem cells become 2 types of white blood cells called myelocytes and monocytes. Some of these bone marrow stem cells never become mature white blood cells. These immature cells, called blasts, are unable to do their usual work. Over time, the myelocytes, monocytes, and blasts crowd out the red blood cells and platelets in the bone marrow. When this happens, infection, anemia, or easy bleeding may occur.
Myelodysplastic syndromes (MDS) occur less often in children than in adults. In MDS, the bone marrow makes too few red blood cells, white blood cells, and platelets. These blood cells may not mature and enter the blood. The treatment for MDS depends on how low the numbers of red blood cells, white blood cells, or platelets are. Over time, MDS may become AML.
Transient myeloproliferative disorder (TMD) is a type of MDS. This disorder of the bone marrow can develop in newborns who have Down syndrome. It usually goes away on its own within the first 3 weeks of life. Infants who have Down syndrome and TMD have an increased chance of developing AML before the age of 3 years.
This summary is about childhood AML, childhood CML, JMML, and MDS. See the following PDQ summaries for more information about other types of leukemia and diseases of the blood and bone marrow in children and adults:
Cancer treatment with certain anticancer drugs and/or radiation therapy may cause therapy -related AML (t-AML) or therapy-related MDS (t-MDS). The risk of these therapy-related myeloid diseases depends on the total dose of the anticancer drugs used and the radiation dose and treatment field. Some patients also have an inherited risk for t-AML and t-MDS. These therapy-related diseases usually occur within 7 years after treatment, but are rare in children.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your child’s doctor if you think your child may be at risk. These and other factors may increase the risk of childhood AML, childhood CML, JMML, and MDS:
The signs and symptoms of TMD may include the following:
The following tests and procedures may be used:
The following test is a type of cytogenetic analysis:
The prognosis (chance of recovery) and treatment options for childhood AML depend on the following:
The prognosis and treatment options for childhood CML depend on how long it has been since the patient was diagnosed and how many blast cells are in the blood.
The prognosis (chance of recovery) and treatment options for JMML depend on the following:
The prognosis (chance of recovery) and treatment options for MDS depend on the following:
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