Chapter 8 - Myelodysplastic Syndromes

Abstract

Myelodysplastic syndromes (MDS) are a group of hematologic disorders distinguished by clonal expansion of defective hematopoietic stem cells leading to abnormal maturation and peripheral blood cytopenia. These disorders are also known as refractory anemias (RA), dysmyelopoietic syndromes, and were originally labeled by some investigators as preleukemias. The peripheral cytopenias may be demonstrated as anemia, thrombocytopenia, granulocytopenia, or pancytopenia. There are two major categories of MDS: primary and secondary. The ineffective hematopoiesis in MDS is demonstrated by mono- or pancytopenia and abnormal morphology in one or more hematopoietic lines in bone marrow and peripheral blood. The ineffective hematopoiesis in MDS is demonstrated by mono- or pancytopenia and abnormal morphology in one or more hematopoietic lines in bone marrow and peripheral blood. According to the WHO classification, there are eight categories of MDS. The low-risk groups include RA with or without ringed sideroblasts and 5q-syndrome. RCMD and RAEB are considered high risk. Clinical features of MDS represent bone marrow failure and cytopenia. Anemia, thrombocytopenia, and/or neutropenia may lead to symptoms such as fatigue, pallor, infection, bruising, and/or bleeding. Diagnosis of MDS is based on a multidisciplinary clinicopathologic approach. It is accomplished by obtaining adequate, pertinent clinical and environmental histories, careful pathologic review of peripheral blood and bone marrow, immunophenotyping, cytogenetic analysis, and molecular genetic studies.