Myelodysplastic Syndrome

1. Myelodysplastic Syndrome

2. Myelodysplastic Syndrome • Group of clonal disorders of hematopoietic stem cells characterized by cellular dysplasia and ineffective hematopoiesis • Results in cytopenias and dysmyelopoiesis • Variable risk of transformation to acute leukemia

3. Pathophysiology • Primary MDS or Secondary MDS • A clonal mutation in hematopoietic stem cells • Bone marrow failure due to ineffective hematopoiesis • Increased cytokines (TNF-a) inhibit hematopoiesis • Increased apoptosis • Results in futile cycling of blood cells with impaired production of mature blood cells

4. Prevalence • Mainly a disorder of older patients, rarely presents before age 50 • Median age is 65 years • Male predominance

5. Clinical Presentation Non specific signs and symptoms of various cytopenias • Fatigue, SOB, exercise intolerance, pallor, tachycardia • Mucosal bleeding, petechiae, ecchymoses • Infection, fever B-symptoms are uncommon Splenomegaly and lymphadenopathy are rare

6. Diagnosis • Anemia uniformly present with decreased reticulocytosis • >50% present with pancytopenia • 50% present with associated neutropenia • <5% isolated neutropenia or thrombocytopenia • Cytopenia with normal or hypercellular bone marrow with single or multi-lineage dysplasia

7. Morphology • Peripheral changes include oval macrocytic red cells, hypogranular granulocytes with the pseudo-Pelger–Huët anomaly, and giant platelets.

8. Morphology • Megaloblastic red-cell precursors with multiple nuclei or asynchronous maturation of the nucleus and the cytoplasm

9. Morphology • Ringed sideroblasts, erythroid precursors with iron-laden mitochondria

10. Classification

11. Classification Cont.

12. Classification cont.