Hematological Concepts and Controversies in Diagnosis and Classification of Myelodysplastic Syndromes

Myelodysplastic syndromes are a heterogeneous group of stem cellmalignancies characterized by dysplastic and ineffective blood cellproduction and variable risk of transformation to acute leukemia. TheFrench-American-British (F AB) group proposed guidelines for thediagnosis and classification of MDS based on myeloid lineagesmorphologically affected by dysplasia and the percentage of blood andbone marrow blasts. The World Health Organization (WHO) updateclassification of MDS not utilizing only morphologic findings but alsoclinical, genetic, immunophenotypic, and biologic information to definedisease entities. Although the diagnosis and classification of most casesof the MDS is usually accomplished without difficulty, a minority ofcases may pose a diagnostic dilemma ,as patients who have hypocellularMDS or MDS with fibrosis, as the criteria for making the diagnosis maybe difficult ifnot impossible to apply.