Leukemia

Myelodysplastic Syndromes

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Myelodysplastic syndromes, also called pre-leukemia or "smoldering" leukemia, are diseases in which the bone marrow -- the spongy tissue inside the large bones -- does not function normally. Bone marrow cells called "blast" develop or mature into several different types of blood cells including red blood cells that carry oxygen and other materials to all tissues of the body; white blood cells that fight infection; and platelets that make the blood clot.

If cells in the bone marrow are injured or abnormal, they may behave abnormally. In myelodysplastic syndromes, the abnormality causes the bone marrow cells or blasts to develop into defective red cells, white cells and platelets. In acute myeloid leukemia, which is the more quickly advancing form of the disease, cells stop maturing altogether.

Myelodysplastic syndromes or acute myeloid leukemia may arise without any known cause or may be due to prior treatment with drugs or radiation for other diseases. Myelodysplastic syndromes occur most often in older people, but they also occur in children and young people.

The name myelodysplastic syndromes is based on how the bone marrow cells and blood cells appear under a microscope. There are five types of myelodysplastic syndromes:

• Chronic myelomonocytic leukemia
• Refractory anemia
• Refractory anemia with excess blasts
• Refractory anemia with excess blasts in transformation
• Refractory anemia with ringed sideroblasts

The symptoms of myelodysplastic syndromes are caused by a shortage of cells ordinarily made by the bone marrow. Too few red cells causes anemia, which makes a child feel tired, unable to exercise, feel short of breath or experience headaches. A lack of white cells makes it hard for children to fight infections. Too few platelets may cause a child to bleed or bruise more easily. Often, myelodysplastic syndromes are diagnosed when children seem to suffering from anemia.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007