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MLAB 1415- Hematology Keri Brophy-Martinez. Chapter 23: Myelodysplastic Syndromes. MYELODYSPLASTIC SYNDROMES.
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MLAB 1415- HematologyKeri Brophy-Martinez Chapter 23: Myelodysplastic Syndromes
MYELODYSPLASTIC SYNDROMES • A group of acquired clonal hematologic disorders characterized by progressive cytopenias in the peripheral blood, reflecting defects in erythroid, myeloid and/or megakaryocytic maturation. • Bone marrow is hyperplastic • The result in impaired hematopoiesis. • The origin is currently unknown. • Affects people over 50 with a slight male predominance
Terms used to describe MDS • Preleukemic leukemia or syndrome • Preleukemic acute human leukemia • Chronic refractory anemia with sideroblasts • Smoldering leukemia
Risk factors • Age • Genetic predisposition • Chromosomes 5,7 and 8 • Down’s, Fanconi’s • Environmental exposures • benzene • Prior therapy • Radiation • Chemotherapy
Clinical findings • Symptoms are related to progressive bone marrow failure • Infections • Bleeding • Weight loss • Cardiovascular • Death usually occurs from infection and/or bleeding or from leukemia if transformation occurs.
FAB classification • Five MDS subtypes: • Refractory anemia (RA) • Refractory anemia with ringed sideroblasts (RARS) • Refractory anemia with excess blasts (RAEB) • Refractory anemia with excess blasts in transformation (RAEB-t) • Chronic myelomonocytic leukemia (CMML)
WHO classification • Refractory anemia (RA) • Anemia is primary finding, but unresponsive to treatment • Refractory anemia with ringed sideroblasts (RARS) • >15% ringed sideroblasts in bone marrow • Refractory cytopenia with multilineage dysplasia (RCMD) • Dysplastic features in at least 10% of cells in two or more lines • RA with excess blasts-1 (RAEB) Cytopenia in at least two lineages, with qualitative abnormalities in all three cell lines
MDS/MPD Diseases • Clonal hematopoietic neoplasms that at initial presentation have some clinical, laboratory or morphological findings of both a MDS/MPD • Abnormalities in the regulation of myeloid proliferation, maturation and cell survival • Diseases • CMML associated with persistent monocytosis • Others
Chronic Myelomonocytic Leukemia (CMML) • Monocytosis • ↑ in mature monocytes (some forms have ↑ monoblasts and promonocytes) • Bone marrow hypercellular • Splenomegaly and hepatomegaly (in patients with high WBC count)
Therapy • Currently, there is no really good treatment for MDS, therefore most therapy is supportive, such as transfusion of blood components and antibiotics. • Treatments that modulate the immune system, such as steroids and interferon have been used to some success. • The only effective treatment is bone marrow transplant, but most patients are too old to survive the rigors of this treatment.
References • McKenzie, Shirlyn B., and J. Lynne. Williams. "Chapter 21." Introduction. Clinical Laboratory Hematology. Boston: Pearson, 2010. Print