The myelodysplastic syndromes.

The myelodysplastic syndromes are a heterogenous group of disorders characterized by abnormalities in the maturation and differentiation of hematopoietic cells. A single diagnostic test is not available but laboratory and clinical features are often characteristic. The French-American-British Co-operative Group has classified these disorders into five subgroups. Despite distinctive morphologic features, this classification identifies only two major prognostic groups. The natural history is variable with some patients rapidly developing acute leukemia, others experiencing complications of pancytopenia in the absence of acute leukemia, while others have minimal symptoms and prolonged survivals. A number of therapeutic modalities have been used including hematinics, steroids, retinoids, low-dose chemotherapy, aggressive chemotherapy, and bone marrow transplantation. Supportive care is the mainstay of treatment for most patients.