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Myelodysplastic Syndrome (MDS)

A picture of a vial of blood with the words "Myelodysplastic syndromes" written beneath it; various other vials of blood and syringes are in the background.

Blood-forming cells in the body’s bone marrow can become abnormal. This can lead to low numbers of one or more types of blood cells. These abnormalities of the bone marrow, called myelodysplastic syndromes are a type of cancer. There are six general types of MDS based on the type, characteristics and/or number of abnormal blood cells.

Normal bone marrow, which is found in the middle of certain bones in the body is composed of blood forming cells, fat cells and supporting tissues. Healthy bone marrow produces immature blood cells which develop into mature, functional red blood cells, white blood cells, and platelets.

These immature cell types in the bone marrow (red blood cells, white blood cells, or platelets) show dysplasia which is an abnormality of the cells. They may accumulate in the bone marrow or have a shortened life span which results in fewer than normal mature blood cells in the circulation. There may also be different types of cytopenia (low blood counts) of the different types of cells that are responsible for some of the symptoms including infection, anemia, spontaneous bleeding, or easy bruising. 

There are different types of MDS and are classified based on their appearance under a microscope, certain chromosomal changes and other criteria.

Risk Factors

Risk factors include:

Age: MDS is most commonly diagnosed in the older population (over age 65).

Medical History: Patients who have had previous cancer treatments (chemotherapy and radiation therapy) are at a higher risk.

Chemical Exposure: Long-term exposure to certain environmental or industrial chemicals, including tobacco smoke, pesticides, fertilizers, and solvents such as benzene increase a person’s risk. Exposure to heavy metals like lead or mercury also cause a person to have an increased risk.

Smoking: (it is known that the risk of developing AML (a type of MDS) is 1.6 times greater for smokers than for non-smokers.)

Signs and symptoms for MDS vary depending on the type of blood cell that is affected

Red blood cells, which are the most common type of blood cell, carry oxygen from the lungs throughout the body and carbon dioxide back to the lungs. Having a low red blood cell count causes anemia, which depending on its severity can have several symptoms including:

  • Fatigue

  • Shortness of breath

  • Pale skin

  • Heart palpitations

  • Chest pain

White blood cells that guard the body against infection have different types of cells. The most common is the neutrophil. Having a low number of neutrophils in the blood is a condition called neutropenia which can lead to severe infections including:

  • Skin infections

  • Nasal congestion / sinus infections

  • Lung infections including cough / shortness of breath

  • Urinary tract infections

  • Fever

Platelets which are a type of blood cell help the blood to clot. A low platelet count called thrombocytopenia can result in:

  • Abnormal bleeding including nosebleeds and bleeding gums

  • Bruising


  • Blood work including a complete blood count (CBC) which measures the numbers of red and white blood cells as well as platelets.

  • A microscopic examination of the blood or bone marrow examining the different types of cells and the appearance of their cells to see if they are normal and healthy appearing.

  • The pathologist will be particularly interested in determining what percentage of the cells are very early types of blood cells are called blasts. With MDS, these blasts don’t develop properly. For MDS to be confirmed, patients will have <20% of blasts.

  • Bone marrow biopsy and possible molecular testing of the bone marrow sample

  • Chromosome and/or DNA analysis of blood cells and bone marrow sample.


Treatment for MDS varies based on symptoms, state of disease, and quality of life. All patients will continue to require routine bloodwork and monitoring of symptoms. Other treatment may include:

  • Supportive care such as antibiotics to treat infections or red blood cell or platelet transfusions to improve anemia and prevent bleeding.

  • Red blood cell stimulating growth factors

  • Chemotherapy

  • Stem cell transplant

Helpful Patient Resources:

We understand that receiving a cancer diagnosis can be a very scary and it is an emotional time for the patient and their families. It is very important to discuss any questions or concerns you may have with your oncologist / hematologist. We highly recommend that if you do any research about your disease, that you do so only with reputable sources. For your convenience, we’ve listed some below.

National Cancer Institute

Myelodysplastic Syndromes Treatment (PDQ®)–Patient Version

American Cancer Society

What Are Myelodysplastic Syndromes?

Types of Myelodysplastic Syndromes

Key Statistics for Myelodysplastic Syndromes

National Comprehensive Cancer Network

Guidelines for Patients