Myelodysplastic syndromes (MDS) represent a heterogeneous group of hematologic disorders characterized by ineffective hematopoiesis and an increased risk of developing acute myeloid leukemia. In this educational article the general aspects of the physiopathology, diagnosis, and histopathological features of MDS and their role in differential diagnosis, classification and prognostic categorization are presented. The importance of clinical and laboratory evaluations, including peripheral blood and bone marrow analyses, including morphology - aspirate and core biopsy, cytogenetics, immunophenotype and careful serial follow-up is emphasized. Definite diagnosis of MDS, especially in low-risk subtypes, should consider the exclusion of disorders with reactive bone marrow alterations, such as viral infections for example HIV. The new revised World Health Organization (WHO-2008) classification is presented and discussed.
Myelodysplastic syndromes; myeloproliferative disorders; diagnostic criteria; histopathology
