Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal stem cell disorders characterized by ineffective hematopoiesis and peripheral cytopenias. MDS often affects older patients and can progress to acute leukemia. The pathophysiology involves initiating lesions in stem cells that give rise to clones with mutations promoting additional genetic changes and ineffective hematopoiesis. Clinical features include cytopenias and dysplastic changes in the bone marrow. MDS is classified according to the French-American-British system based on peripheral blood and bone marrow findings. Prognosis is assessed using the International Prognostic Scoring System. Treatment options include supportive care, stem cell transplantation, cytokine therapy, chemotherapy, and immunosuppression

1. Myelodysplastic Syndromes Terrance Comeau, M.D., F.R.C.P. 3-25-2002

15. Bizarre erythroid precursors.

16. Bizarre erythroid precursors (clover-leaf nuclei).

17. Ringed Sideroblasts

19. Hyposegmented/ hypogranular neutrophi

20. Pelger-Huet hyposegmentation

21. Abnormal ring nucleus with abnormal granulation pattern.

32. FAB Classification > 1 X 10 9 /L ≤ 20% < 5% CMML 21-30% > 5% RAEB-T 5-20% < 5% RAEB < 5% < 1% > 15% RARS < 5% < 1% RA PB Monocytes BM Blasts PB Blasts % Ringed Sideroblasts

36. Marrow Blast % 2 21-30 1.5 11-20 0.5 5-10 0 < 5 IPSS Score Blast %

37. Cytogenetic Features 1.0 Poor Prognosis 0.5 Intermediate Prognosis 0 Good Prognosis IPSS Score Karyotype

38. Cytopenias 0.5 2 or 3 Types 0 None or 1 Type IPSS Score Cytopenia

39. Overall IPSS Score and Survival 0.4 years High (≥ 2.5) 3.5 years 1.2 years Intermediate 1 (0.5 or 1.0) 2 (1.5 or 2.0) 5.7 years Low (0) Median Survival Overall Score

48. Questions?