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What are Myeloproliferative Neoplasms (MPNs)?

Myeloproliferative Neoplasms (MPNs) are blood cancers that occur when the body makes too many white or red blood cells, or platelets. This overproduction of blood cells in the bone marrow can create problems for blood flow and lead to various symptoms. MPNs were called Myeloproliferative Diseases until 2008 when the World Health Organization reclassified them as cancers and renamed them Myeloproliferative Neoplasms.

There are three main types of MPNs:

  • Polycythemia vera (PV)
  • Essential thrombocythemia (ET) 
  • Myelofibrosis (MF)

Certain leukemias, including chronic myelogenous leukemia, are also now considered Myeloproliferative Neoplasms. Although myeloproliferative neoplasms can pose health risks, people with these conditions often live for many years after diagnosis. The choice of treatment and how well it works depends largely on the type of MPN.

Videos: People Living with MPNs

Polycythemia Vera (PV)

Polycythemia vera (PV) is a rare type of blood cancer. PV occurs when the body makes too many red blood cells. Red blood cells are responsible for carrying oxygen through the body. Too many can cause the blood to become thicker and move more slowly. People with polycythermia vera sometimes have too many white blood cells and platelets as well.

PV is one of three myeloproliferative neoplasms (MPNs).

Risk Factors

The causes of polycythemia are largely unknown. It occurs more often in people over 60, and slightly more often in men. In very rare instances, it runs in families. Most people with this disease have an abnormal change in the JAK2 gene. Other genes may be involved as well.

Signs and Symptoms

The increase in red blood cells can cause the blood to thicken and clot, causing signs and symptoms of polycythemia vera. In early stages, patients have few symptoms. As the disease progresses, the following symptoms may appear:

  • Blood clot 
  • Headache
  • Excessive sweating
  • Blurred vision or blind spots
  • Dizziness
  • Itchiness, especially after a warm shower or bath
  • Redness or a purplish appearance of skin
  • Peptic ulcers
  • Bloat or a feeling of fullness due to enlarged spleen
  • Congestive heart failure or angina
  • Gout/inflammation of joints


Learn About Diagnosis and Treatment Options

Essential Thrombocythemia (ET)

Essential thrombocythemia (ET) is a rare type of blood cancer. ET occurs when the body makes too many platelets, the part of the blood needed for clotting. Researchers are still trying to understand the causes of ET. ET is one of three myeloproliferative neoplasms (MPNs). There is no cure for ET but people with the disease often live normal lives.

Risk Factors

The causes of essential thrombocythemia are largely unknown. It occurs more often in people over 50, and slightly more often in women. It is usually not passed down through families. Approximately half of people with this disease have an abnormal change in the JAK2 gene. Other genes may be involved as well.

Signs and Symptoms

Most people with essential thrombocythemia show no signs or symptoms. If signs and symptoms occur, they may include:

  • Headache
  • Throbbing or burning pain in feet or hands
  • Lightheadedness or dizziness
  • Enlarged spleen
  • Thrombosis (abnormal clotting)
  • Bleeding (less common)
  • Fatigue
  • Weakness
  • Sweating


Learn About Diagnosis and Treatment Options

What is Myelofibrosis?

Since 2010, myelofibrosis (MF) has been considered a form of cancer. It is one of the three most common myeloproliferative neoplasms (MPN) – rare blood diseases that develop when the bone marrow makes too many blood cells. In myelofibrosis, scar tissue forms inside the bone marrow. Primary myelofibrosis develops on its own. Secondary myelofibrosis can result from another bone marrow disorder. In either case, the body is not able to produce blood cells normally.

Risk Factors

Little is known about the causes of primary myelofibrosis. It occurs in both men and women. It is usually diagnosed in people over age 50 but can affect people of any age.

Doctors who study myelofibrosis in a laboratory have found that many people with the disease have mutation (or change) in certain genes, including JAK.

Signs and Symptoms

Myelofibrosis (MF) often develops slowly. Symptoms are seldom seen in the very early stages. The first signs are usually an enlarged spleen or abnormal blood test. As the cancer develops, your normal blood cells do not function correctly and symptoms appear. Check with your doctor if you are experiencing:

  • Fatigue, weakness, or shortness of breath. These symptoms are associated with a decrease in the red blood cells (anemia)
  • Pain or fullness below the ribs on the left side, as a result of an enlarged spleen
  • Enlarged liver
  • Pale skin
  • Easy bruising or bleeding
  • Flat, red, pinpoint spots under the skin caused by bleeding
  • Excessive night sweats
  • Fever
  • Frequent infections, due to a low white blood cell count
  • Bone or joint pain
  • Weight loss
  • Itchiness

Diagnosis

Most people diagnosed with myelofibrosis do not have obvious symptoms. Common first symptoms include an enlarged spleen or abnormal blood count.

In people who have no symptoms, myelofibrosis may be suspected when a regular medical checkup shows an enlarged spleen and abnormal blood test results.

The results of a blood test that suggest a diagnosis of MF often include:

  • A decrease in the number of red blood cells (anemia) below the normal range
  • An increase or decrease in the number of white blood cells
  • An increase in platelets above the normal range (occurs in about one-third of MF patients)
  • A mild to moderate decrease in platelets below the normal range (occurs in about one-third of MF patients) 

If you have symptoms, you may be referred to a doctor who specializes in blood cancers for further testing of the blood and bone marrow, including:

  • Complete blood count: a blood test that measures the white blood cells, red blood cells, and platelets in the blood 
  • Ultrasound: uses high-frequency sound waves to look at organs and structures inside the body
  • MRI: a scan that uses magnets and radio frequency waves to produce images of the inside of the body
  • Bone marrow examination: removal of a small amount of your bone and bone marrow for laboratory analysis
  • Genetic tests: analysis of a sample of your blood or bone marrow tissue to study the genetic make-up

If these tests confirm a diagnosis of myelofibrosis, you will continue to see a hematologist/oncologist, the doctor who treats blood cancers.

Myelofibrosis is not always curable so it is important to think about how your life may change. A chronic illness becomes part of who you are and how you live your life. A diagnosis of myelifibrosis may require changes in your routine, how you care for yourself or what you need from others in your life. It does not, however, define you. You are not your disease.

Learn More about Myelofibrosis Treatment and Side Effects