Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, leading to peripheral cytopenias—particularly anemia, neutropenia, and thrombocytopenia—and a predisposition to progression into acute myeloid leukemia (AML), with approximately 10–20% of cases evolving to AML. The disease results from genetic and epigenetic abnormalities in bone marrow stem cells, causing dysplastic morphologic changes and impaired differentiation across myeloid lineages. MDS is defined pathologically by the presence of dysplasia in one or more blood cell lines, including ringed sideroblasts in certain subtypes, and is classified based on morphology, blast percentage, and cytogenetic features (e.g., refractory anemia, refractory anemia with excess blasts). It commonly affects older adults, with diagnosis typically occurring after age 60, and often remains under-recognized due to nonspecific symptoms such as fatigue, weakness, shortness of breath, infections, bruising, and bleeding. Risk factors include prior exposure to chemotherapy or radiation, and secondary MDS can arise following treatment for other cancers. Management strategies vary according to risk stratification and may include supportive care with transfusions, growth factors, hypomethylating agents, immunomodulatory drugs, chemotherapy, or allogeneic stem cell transplantation in eligible patients. MDS is considered a premalignant condition and requires careful monitoring due to its potential to transform into overt AML.

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