The typical survival time following diagnosis is 2.5 years. The conditions were first recognized in the early 1900s. The current name came into use in 1976. Signs and symptoms
Signs and symptoms are nonspecific and generally related to the blood cytopenias:

Anemia (low RBC count or reduced hemoglobin) – chronic tiredness, shortness of breath, chilled sensation, sometimes chest pain
Neutropenia (low neutrophil count) – increased susceptibility to infection
Thrombocytopenia (low platelet count) – increased susceptibility to bleeding and ecchymosis (bruising), as well as subcutaneous hemorrhaging resulting in purpura or petechiaeMany individuals are asymptomatic, and blood cytopenia or other problems are identified as a part of a routine blood count:
Neutropenia, anemia, and thrombocytopenia
Splenomegaly or rarely hepatomegaly
Abnormal granules in cells, abnormal nuclear shape and size
Chromosome abnormality, including chromosomal translocations and abnormal chromosome numberAlthough some risk exists for developing acute myelogenous leukemia, about 50% of deaths occur as a result of bleeding or infection. However, leukemia that occurs as a result of myelodysplasia is notoriously resistant to treatment. Anemia dominates the early course. Most symptomatic patients complain of the gradual onset of fatigue and weakness, dyspnea, and pallor, but at least half the patients are asymptomatic and their MDS is discovered only incidentally on routine blood counts. Previous chemotherapy or radiation exposure is an important factor in the persons medical history. Fever, weight loss and splenomegaly should point to a myelodysplastic/myeloproliferative neoplasm (MDS/MPN) rather than pure myelodysplastic process.
Classification
World Health Organization
In the late 1990s, a group of pathologists and clinicians working under the World Health Organization (WHO) modified this classification, introducing several new disease categories and eliminating others. In 2008, the WHO developed a new classification scheme that is based more on genetic findings, but morphology of the cells in the peripheral blood, bone marrow aspirate, and bone marrow biopsy are still the screening tests used to decide which classification is best and which cytogenetic aberrations may be related.The list of dysplastic syndromes under the new WHO system includes:

Note : not all physicians concur with this reclassification, because the underlying pathology of this disease is not well understood. Myelodysplastic syndrome unclassified
The WHO has proposed a criterion for diagnosis and classification of MDS that may apply to most cases. However, occasional cases are difficult to classify into defined categories because of one or more unusual features:
Rare cases with less than 5% blast will present with Auer rods. These cases usually have the features of RAMD. Occasionally, cases of MDS present with isolated neutropenia or thrombocytopenia without anemia and with dysplastic changes confined to the single lineage. The terms refractory neutropenia and refractory thrombocytopenia have sometimes been used to describe these cases. A diagnosis of MDS in patients with neutropenia or thrombocytopenia without anemia should be made with caution. Patients with RA or RAEB occasionally present with leukocytosis or thrombocytosis instead of the usual cytopenia. Management
The goals of therapy are to control symptoms, improve quality of life, improve overall survival, and decrease progression to AML.