What is MDS and MPN (bone marrow disorders)?

Bone marrow is the soft, spongy tissue inside your bones. It makes your blood cells. Red blood cells carry oxygen. White blood cells fight infection. Platelets help your blood clot. MDS and MPN are groups of conditions that start in the stem cells of the bone marrow. A stem cell is a young cell that can grow into any type of blood cell. In these conditions, one stem cell picks up gene changes and starts making copies of itself. Doctors call this a clone.

When should I call my care team?

Fever of 100.4 F (38 C) or higher, or shaking chills; Swelling, pain, or warmth in one leg, or sudden shortness of breath or chest pain (possible blood clot); Sudden weakness or numbness on one side, trouble speaking, face drooping, or sudden vision loss (possible stroke); Bleeding that will not stop, nosebleeds that last more than 10 minutes, black or bloody stools, or vomiting blood; Many new bruises or tiny red spots on the skin; Sudden, severe belly pain, especially on the left side (possible spleen problem); Feeling very weak, dizzy, or short of breath, or a racing heart; Confusion, trouble walking, or vision problems while taking fedratinib; A painful rash with blisters on one side of the body (possible shingles); If it feels very bad, call 911.

MDS and MPN (bone marrow disorders)

MDS and MPN are long-term bone marrow conditions that range from slow and mild to more serious, and many people live for years with good care and close follow-up.

Hi, I'm Rosa. Today we'll go through two kinds of bone marrow conditions, called myelodysplastic syndromes and myeloproliferative neoplasms together, one step at a time. I'll keep it simple, and you can pause me, go back, or skip ahead whenever you like. Just so you know, this is for learning only. It is not medical advice, so please check everything with your own doctor and care team. Okay, let's get started.

What these conditions are

Let's start with the basics. Bone marrow is the soft tissue inside your bones. It makes your blood cells. In myelodysplastic syndromes, the marrow makes cells that do not grow up right. This leads to low blood counts. In myeloproliferative neoplasms, the marrow makes too many blood cells. A big worry then is blood clots. Doctors count these as types of blood cancer. That word can be scary. But many people live for many years. You did not cause this.

The main types

Let's talk briefly about the types. Lower risk myelodysplastic syndrome tends to grow slowly. The main problem is usually low red cells. Higher risk myelodysplastic syndrome needs stronger treatment. Polycythemia vera means too many red blood cells. Essential thrombocythemia means too many platelets. Myelofibrosis means scar tissue builds up in the marrow. Some conditions have features of both groups. Your care team will tell you which type you have.

Tests you may have

Now let's talk about tests. A complete blood count measures your red cells, white cells, and platelets. A blood smear looks at your cells under a microscope. Other blood tests rule out things like low vitamins. A bone marrow biopsy takes a small sample from the hip bone. You get numbing medicine first. Chromosome tests and gene tests look for changes in the cells. A scan can measure the size of your spleen. A symptom form helps track how you feel.

Risk levels

Next up, let's talk about risk levels. These conditions are not staged like many cancers. Instead, doctors use risk scores. A risk score adds up results from your tests. It places you in a group, from lower to higher risk. Why do doctors use them? They help decide how strong treatment should be. They also help everyone talk the same language. A risk score is an average for groups of people. It cannot tell exactly what will happen to you.

Gene and lab tests to know

Before we move to treatment, there are some things to know. Gene changes in the marrow cells help confirm the diagnosis. They also help guide treatment. Most of these changes are not passed down in families. There are many different markers. Each one has a different role. Some point to a specific medicine. Some show how the condition may act. Your doctor will tell you which ones you have. They will also explain what they mean for you. You can read more in the guide. The Questions to ask page can help too.

Main treatment options

Now let's look at treatment. Many people with lower risk disease start with close watching. Transfusions can ease tiredness and bleeding. Shots can help the marrow make more red cells. Some medicines help the marrow work better and slow the disease. Removing some blood, plus low dose aspirin, helps lower clot risk. Pills or shots can lower high blood counts. Other pills can shrink a large spleen and ease symptoms. A stem cell transplant may be discussed for some people. Clinical trials are research studies that may offer new options. Ask your care team.

Side effects and what helps

Let's talk about side effects. Many treatments can lower blood counts at first. Your team checks your blood often. Low white cells raise the risk of infection. Wash your hands often, and call for a fever. Feeling tired is very common. Short walks and good sleep help. Itching after a warm shower is common in polycythemia vera. Cooler showers and gentle lotion may help. Some shots can cause flu like feelings. We have a whole side effects guide on this site.

Living well with it

Last, let's talk about living well. For most people, these are long term conditions. You may have blood tests for many years. Keep a record of your counts and how you feel. Do not smoke, and stay active to lower clot risk. Tell every doctor and dentist about your condition. Support groups and counselors can help. Call right away for a fever. Also call for one swollen leg or sudden trouble breathing. Signs of a stroke need help right away too. If it feels very bad, call 911. Also see our new Screening, prevention and survivorship section.

You did great today. That was a lot, and you took it one step at a time. Write down your questions and bring them to your next visit. Call your care team any time something worries you. You are not alone in this.

Call your care team right away if you have

Fever of 100.4 F (38 C) or higher, or shaking chills
Swelling, pain, or warmth in one leg, or sudden shortness of breath or chest pain (possible blood clot)
Sudden weakness or numbness on one side, trouble speaking, face drooping, or sudden vision loss (possible stroke)
Bleeding that will not stop, nosebleeds that last more than 10 minutes, black or bloody stools, or vomiting blood
Many new bruises or tiny red spots on the skin
Sudden, severe belly pain, especially on the left side (possible spleen problem)
Feeling very weak, dizzy, or short of breath, or a racing heart
Confusion, trouble walking, or vision problems while taking fedratinib
A painful rash with blisters on one side of the body (possible shingles)
If it feels very bad, call 911.

Side effects: what helps

Sources

Quick answers

What is MDS and MPN (bone marrow disorders)?: Bone marrow is the soft, spongy tissue inside your bones. It makes your blood cells. Red blood cells carry oxygen. White blood cells fight infection. Platelets help your blood clot. MDS and MPN are groups of conditions that start in the stem cells of the bone marrow. A stem cell is a young cell that can grow into any type of blood cell. In these conditions, one stem cell picks up gene changes and starts making copies of itself. Doctors call this a clone.
When should I call my care team?: Fever of 100.4 F (38 C) or higher, or shaking chills; Swelling, pain, or warmth in one leg, or sudden shortness of breath or chest pain (possible blood clot); Sudden weakness or numbness on one side, trouble speaking, face drooping, or sudden vision loss (possible stroke); Bleeding that will not stop, nosebleeds that last more than 10 minutes, black or bloody stools, or vomiting blood; Many new bruises or tiny red spots on the skin; Sudden, severe belly pain, especially on the left side (possible spleen problem); Feeling very weak, dizzy, or short of breath, or a racing heart; Confusion, trouble walking, or vision problems while taking fedratinib; A painful rash with blisters on one side of the body (possible shingles); If it feels very bad, call 911.

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.