Myelodysplastic/Myeloproliferative Diseases

Disease Sub-types
Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia is a disease in which too many myelocytes and monocytes (immature white blood cells) are made in the bone marrow.

In CMML, the body tells too many blood stem cells to develop into two types of white blood cells called myelocytes and monocytes. Some of these blood stem cells never become mature white blood cells. These immature white blood cells are called blasts. 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.

Older age and being male increase the risk of developing chronic myelomonocytic leukemia.

Anything that increases your chance of getting a disease is called a risk factor. Possible risk factors for CMML include the following:

  • Older age.
  • Being male.
  • Being exposed to certain substances at work or in the environment.
  • Being exposed to radiation.
  • Past treatment with certain anticancer drugs.

Possible signs of chronic myelomonocytic leukemia include fever, feeling very tired, and weight loss.

These and other symptoms may be caused by CMML. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Fever for no known reason.
  • Infection.
  • Feeling very tired.
  • Weight loss for no known reason.
  • Easy bruising or bleeding.
  • Pain or a feeling of fullness below the ribs.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options for CMML depend on the following:

  • The number of white blood cells or platelets in the blood or bone marrow.
  • Whether the patient is anemic.
  • The amount of blasts in the blood or bone marrow.
  • The amount of hemoglobin in red blood cells.
  • Whether there are certain changes in the chromosomes.
Juvenile Myelomonocytic Leukemia

Juvenile myelomonocytic leukemia is a childhood disease in which too many myelocytes and monocytes (immature white blood cells) are made in the bone marrow.

Juvenile myelomonocytic leukemia is a rare childhood cancer that occurs more often in children younger than 2 years. Children who have neurofibromatosis type 1 and males have an increased risk of developing juvenile myelomonocytic leukemia.

In JMML, the body tells too many blood stem cells to develop into two types of white blood cells called myelocytes and monocytes. Some of these blood stem cells never become mature white blood cells. These immature white blood cells are called blasts. 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.

Possible signs of juvenile myelomonocytic leukemia include fever, feeling very tired, and weight loss.

These and other symptoms may be caused by JMML. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Fever for no known reason.
  • Having infections, such as bronchitis or tonsillitis.
  • Feeling very tired.
  • Easy bruising or bleeding.
  • Skin rash.
  • Painless swelling of the lymph nodes in the neck, underarm, stomach, or groin.
  • Pain or a feeling of fullness below the ribs.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options for JMML depend on the following:

  • The age of the child at diagnosis.
  • The number of platelets in the blood.
  • The amount of a certain type of hemoglobin in red blood cells.
Atypical Chronic Myelogenous Leukemia

Atypical chronic myelogenous leukemia is a disease in which too many granulocytes (immature white blood cells) are made in the bone marrow.

In atypical chronic myelogenous leukemia (aCML), the body tells too many blood stem cells to develop into a type of white blood cell called granulocytes. Some of these blood stem cells never become mature white blood cells. These immature white blood cells are called blasts. Over time, the granulocytes and blasts crowd out the red blood cells and platelets in the bone marrow.

The leukemia cells in aCML and chronic myelogenous leukemia (CML) look alike under a microscope. However, in aCML a certain chromosome change, called the "Philadelphia chromosome" is not present.

Possible signs of atypical chronic myelogenous leukemia include easy bruising or bleeding and feeling tired and weak.

These and other symptoms may be caused by aCML. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Shortness of breath.
  • Pale skin.
  • Feeling very tired and weak.
  • Easy bruising or bleeding.
  • Petechiae (flat, pinpoint spots under the skin caused by bleeding).
  • Pain or a feeling of fullness below the ribs on the left side.

Certain factors affect prognosis (chance of recovery).

The prognosis (chance of recovery) for aCML depends on the number of red blood cells and platelets in the blood.

Myelodysplastic/Myeloproliferative Disease, Unclassifiable

Myelodysplastic/myeloproliferative disease, unclassifiable, is a disease that has features of both myelodysplastic and myeloproliferative diseases but is not chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia, or atypical chronic myelogenous leukemia.

In myelodysplastic/myeloproliferative disease, unclassifiable (MDS/MPD-UC), the body tells too many blood stem cells to develop into red blood cells, white blood cells, or platelets. Some of these blood stem cells never become mature blood cells. These immature blood cells are called blasts. Over time, the abnormal blood cells and blasts in the bone marrow crowd out the healthy red blood cells, white blood cells, and platelets.

MDS/MPD-UC is a very rare disease. Because it is so rare, the factors that affect risk and prognosis are not known.

Possible signs of chronic myelomonocytic leukemia include fever, feeling very tired, and weight loss.

These and other symptoms may be caused by MDS/MPD-UC. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Fever or frequent infections.
  • Shortness of breath.
  • Feeling very tired and weak.
  • Pale skin.
  • Easy bruising or bleeding.
  • Petechiae (flat, pinpoint spots under the skin caused by bleeding).
  • Pain or a feeling of fullness below the ribs.

Cancer information from the NCI PDQ service