What Are Chronic Myeloproliferative Disorders?

Medically Reviewed by Murtaza Cassoobhoy, MD on May 23, 2023
5 min read

Chronic myeloproliferative disorders (MPD) are rare blood cancers that have many different symptoms, yet no clear cause. Because of that, they can be tricky to diagnose. Years of care and treatment are common.

Your blood contains red blood cells, white blood cells, and platelets. Each of these has a crucial job to do. Your red blood cells carry oxygen throughout your body. White blood cells protect your body from germs. Platelets control your bleeding.

All of these parts of blood are made in your bone marrow, the soft tissue inside your bones.

If you have MPD, your bone marrow makes too many deformed red blood cells, white blood cells, or platelets. These pile up in your blood.

There are six different types of MPD. The kind you have depends on which blood cells your body is making in excess. The six types are:

  • Chronic myelogenous leukemia (CML): Too many immature white blood cells are being made in your bone marrow.
  • Polycythemia vera: You have an increased number of red blood cells. Often, there’s an excess of platelets and white blood cells, too. People with this have too many immature white and red blood cells. The web of fibers inside the bone marrow becomes thick, like scar tissue. This causes fewer and fewer red blood cells to be made.
  • Primary myelofibrosis (chronic idiopathic myelofibrosis): People with this have too many immature white and red blood cells. The web of fibers inside the bone marrow becomes thick, like scar tissue. This causes fewer and fewer red blood cells to be made.
  • Essential thrombocythemia: If you have this kind of MPD, you have too many platelets.
  • Chronic neutrophilic leukemia: This disorder causes you to have a surplus of neutrophils -- a certain type of white blood cell -- in your bloodstream.
  • Chronic eosinophilia leukemia: Eosinophils are another type of white blood cell. Your body produces them when you’ve been exposed to an allergen or parasite. People with this type of MPD have a high number of them in their blood.

Any of these disorders can also lead to acute leukemia. This means that your bone marrow is making deformed white blood cells.

Doctors are still trying to answer this question. So far, what’s known is that if you have MPD, you have a gene mutation (change) on your bone marrow cells. This keeps your body from being able to make the right amount and kind of blood cells.

You aren’t born with this mutation. It happens when you’re an adult. Some theories are that having a virus or being around toxic chemicals or radiation can cause this to happen.

Only in very rare cases do MPDs run in families.

Signs that you have one of these disorders include:

Major complications of these disorders include:

  • Excessive bleeding, which can happen with a minor cut, bruising or when capillaries break under the skin
  • Blood clots (thrombosis)
  • The disease changing into leukemia

In the early stages of MPD, many people don’t have any symptoms. This makes it a challenge to diagnose. Any signs that do show up are often thought to be other, more common health problems. It is often found by chance when you have routine blood work.

You may need to see a doctor who specializes in MPD to be diagnosed. Blood tests will be ordered to get more details about your health. To confirm the diagnosis, a bone marrow biopsy is often done.

To do this, a hollow needle will be put into your hip bone or breastbone. Then a sample of blood, bone marrow, or bone will be removed and sent to a lab. There, it can be checked under a microscope to look for cancer cells.

These disorders are difficult to cure. Your doctor will typically focus on trying to get your blood cells back to normal levels and reducing the risk for major complications. The treatment depends on which myeloproliferative disorder you have. Some of the most common treatments are:

Chemotherapy: Powerful medications are used to kill extra blood cells in your body. You may get this through an IV, or you could be given a pill that you take by mouth.

Radiation therapy: High-powered X-rays or other types of radiation can lower the number of blood cells you have and may relieve your symptoms.

Phlebotomy: A unit of blood can be removed from you in order to decrease red blood cell counts.

Gene therapy: New medications may be able to block or repair the mutated gene that causes MPD.

Hormone therapy: Certain hormones can extend the life of your normal blood cells or push your bone marrow to make more. Hormone therapy may also lessen some side effects of MPD.

Stem cell transplant: If you have a severe case of MPD, you might be able to have a stem cell transplant. During this procedure, healthy bone marrow, often from a bone marrow donor, is transferred to you. This is the only treatment that has the potential to cure MPD, but it’s not for everyone.

Surgery: If your spleen is swollen, it may be removed during a surgery called a splenectomy.

Clinical trials: These studies test new cancer treatments to see if they work as well or better than what’s already being used. In some cases, they may be your best choice. You may be among the first to try a new cancer medication or treatment, while helping with a crucial part of cancer research.

Watchful waiting: If your MPD is very mild and you have no symptoms, your doctor may also suggest you wait to start any treatment. Some people are fine for several years with only a daily aspirin to prevent blood clots and regular doctor visits.