Myelodysplastic syndrome

: One of a group of disorders of the bone marrow which have in common abnormalities in cell development of one or more of the cells lines normally found in the bone marrow. Patients can develop a variety of symptoms related to anemia, low or high white cell count, infections, and bleeding problems. This condition may progress and become acute leukemia. The seven well recognized myelodysplastic syndromes include refractory anemia (RA), refractory anemia with ringed sideroblasts (RARS), refractory anemia with excess blasts (RAEB), refractory anemia with excess blasts in transformation (RAEB-T), chronic myelomonocytic leukemia (CMML), chronic myelomonocytic leukemia in transformation (CMML-T), and unclassified myelodysplastic syndrome.

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myelodysplastic syndrome n any of a group of bone marrow disorders that are marked esp. by an abnormal reduction in one or more types of circulating blood cells due to defective growth and maturation of blood-forming cells in the bone marrow and that sometimes progress to acute myelogenous leukemia called also myelodysplasia

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any of a group of related bone marrow disorders of varying duration preceding the development of overt acute myelogenous leukemia; they are characterized by abnormal hematopoietic stem cells, anemia, neutropenia, and thrombocytopenia. Splenomegaly, hepatomegaly, and lymphadenopathy may not occur until the onset of leukemia, which is sometimes sudden and fulminating. Called also preleukemia.