Key Points for This Section

Chronic idiopathic myelofibrosis is a disease in which abnormal blood cells and fibers build up inside the bone marrow. Possible signs of chronic idiopathic myelofibrosis include pain below the ribs on the left side and feeling very tired. A special blood test is used to diagnose chronic idiopathic myelofibrosis. Certain factors affect prognosis (chance of recovery) and treatment options for chronic idiopathic myelofibrosis.

Chronic idiopathic myelofibrosis is a disease in which abnormal blood cells and fibers build up inside the bone marrow.

The bone marrow is made of tissues that make blood cells (red blood cells, white blood cells, and platelets) and a web of fibers that support the blood-forming tissues. In chronic idiopathic myelofibrosis, large numbers of blood stem cells develop into blood cells that do not mature properly (blasts). The web of fibers inside the bone marrow also becomes very thick (like scar tissue) and slows the blood-forming tissue’s ability to make blood cells. This causes the blood-forming tissues to make fewer and fewer blood cells. In order to make up for the low number of blood cells made in the bone marrow, the liver and spleen begin to make the blood cells.

Possible signs of chronic idiopathic myelofibrosis include pain below the ribs on the left side and feeling very tired.

Chronic idiopathic myelofibrosis often does not cause early symptoms. It is sometimes found during a routine blood test. The following symptoms may be caused by chronic idiopathic myelofibrosis or by other conditions. A doctor should be consulted if any of these problems occur:

• Feeling pain or fullness below the ribs on the left side.
• Feeling full sooner than normal when eating.
• Feeling very tired.
• Shortness of breath.
• Easy bruising or bleeding.
• Petechiae (flat, red, pinpoint spots under the skin that are caused by bleeding).
• Fever.
• Night sweats.
• Weight loss.

A special blood test is used to diagnose chronic idiopathic myelofibrosis.

In addition to a complete blood count, bone marrow aspiration and biopsy, and cytogenetic analysis, a peripheral blood smear is used to diagnose chronic idiopathic myelofibrosis. A peripheral blood smear is a procedure in which a sample of blood is checked for tear drop-shaped red blood cells, the number and kinds of white blood cells, the number of platelets, and the presence of blast cells.

Certain factors affect prognosis (chance of recovery) and treatment options for chronic idiopathic myelofibrosis.

Prognosis (chance of recovery) depends on the following:

• The age of the patient.
• The number of abnormal red blood cells and white blood cells.
• The number of blasts in the blood.
• Whether there are certain changes in the chromosomes.
• Whether the patient has symptoms such as fever, night sweats, or weight loss.

Glossary Terms

Not normal. An abnormal lesion or growth may be cancer, premalignant (likely to become cancer), or benign (not cancer).

A process in which anything complex is separated into simple or less complex parts.

An immature blood cell.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.

The removal of a small sample of bone marrow (usually from the hip) through a needle for examination under a microscope.

The removal of a sample of tissue from the bone marrow with a needle for examination under a microscope.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.

A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called agnogenic myeloid metaplasia, idiopathic myelofibrosis, myelosclerosis with myeloid metaplasia, and primary myelofibrosis.

A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count and CBC.

The study of chromosomes and chromosomal abnormalities.

The process of identifying a disease, such as cancer, from its signs and symptoms.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (red blood cells, white blood cells, platelets, etc.) and see whether the cells look normal.

Pinpoint, unraised, round red spots under the skin caused by bleeding.

A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots. Also called thrombocyte.

The likely outcome or course of a disease; the chance of recovery or recurrence.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

An organ that is part of the lymphatic system. The spleen makes lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. It is located on the left side of the abdomen near the stomach.

A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A group or layer of cells that work together to perform a specific function.

A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.