Bone Cancer Myeloproliferative Disorders Jmml

Juvenile myelomonocytic leukemia (JMML) is a rare leukemia that develops almost exclusively in children under age five. For unknown reasons, the child’s bone marrow starts to make white blood cells that do not mature correctly.

Unlike normal, healthy cells, these immature white cells (called blasts) do not receive the body’s signals telling them to stop reproducing. The immature cells, which do not work properly, eventually crowd out healthy blood cells.

JMML Symptoms

Signs and symptoms that you might notice in a child with JMML include:

  • Bleeding
  • Cough
  • Fever
  • Infection
  • Pallor (pale skin)
  • Poor weight gain
  • Skin rash that is often red and may be discolored but not raised, or small and raised but not containing pus.

Signs that a doctor may identify in a child with JMML include:

  • Enlarged liver
  • Enlarged lymph nodes
  • Enlarged spleen
  • High white blood cell count in blood or high monocyte count (a monocyte is a specific kind of white blood cell)
  • Low platelet count (thrombocytopenia)
  • Low red blood cell count (anemia).

A healthcare provider diagnoses juvenile myelomonocytic leukemia through blood tests and bone marrow tests.

JMML Prognosis and Treatment

The first phase of treatment for JMML leukemia is usually to deal with symptoms such as anemia, bleeding or infection. Treatments may include blood transfusions, spleen removal and antibiotics. The child might also receive biological therapy with substances that may help the body’s immune system fight cancer.

Chemotherapy for JMML is rarely a cure, but it may be used to control the leukemia until the child can receive a stem cell transplant. According to the National Cancer Institute (2010), in the past, when chemotherapy was the only available treatment, prognosis was poor and more than 90 percent of children with juvenile myelomonocytic leukemia died.

A stem cell transplant (also called a bone marrow transplant) is the best option for curing JMML leukemia, offering a survival rate of about 50 percent, according to the National Cancer Institute (2010). Treatment begins with high-dose chemotherapy, sometimes combined with radiation therapy, to destroy all the body’s bone marrow, stem cells and cancer cells. Then, the child receives healthy stem cells from another person. These healthy stem cells help restore normal blood production.

According to the JMML Foundation (2009), as many as 50 percent of children have a relapse after a stem cell transplant; however, a second transplant produces a significant number of complete remissions and long-term cures.


Children’s Hospital Boston. (2010). Juvenile myelomonocytic leukemia. Retrieved October 19, 2010, from

National Cancer Institute. (2010). Juvenile myelomonocytic leukemia. Retrieved October 19, 2010, from

The JMML Foundation. (2009). About JMML. Retrieved October 19, 2010, from