Myelodysplastic syndrome

The myelodysplastic syndromes (also known as MDS or myelodysplasia) are hematological (i.e., blood-related) medical conditions with ineffective production (or "dysplasia") of all blood cells.

Patients with MDS can develop severe anemia and require blood transfusions. In some cases, the disease worsens and the patient develops cytopenias (low blood counts) caused by progressive bone marrow failure. The outlook in MDS depends on the type and severity. Many people live normal lifespans with MDS.

The myelodysplastic syndromes are all disorders of the hematopoietic stem cells in the bone marrow (only related to myeloid lineage). In MDS, hematopoiesis (i.e., blood production) is disorderly and ineffective. The number and quality of blood-forming cells decline irreversibly, further impairing blood production. The mean age of onset of MDS is 68 years.

Classification

French-American-British (FAB) classification

In 1974 and 1975, a group of pathologists from France, the US, and Britain produced the first widely used classification of these diseases. This French-American-British classification was published in 1976, and revised in 1982. It was used by pathologists and clinicians for almost 20 years. Cases were classified into five categories: