![]() Tuncer MA, Pagliuca A, Hicsonmez G, et al.: Primary myelodysplastic syndrome in children: the clinical experience in 33 cases.Sekeres MA, Schoonen WM, Kantarjian H, et al.: Characteristics of US patients with myelodysplastic syndromes: results of six cross-sectional physician surveys.Ma X, Does M, Raza A, et al.: Myelodysplastic syndromes: incidence and survival in the United States.Organic chemicals (e.g., benzene, toluene, xylene, and chloramphenicol). ![]() Potential environmental risk factors for developing MDS include exposure to the following: Hypoplastic myelodysplastic patients tend to have profound cytopenias and may respond more frequently to immunosuppressive therapy.Īpproximately 90% of MDS cases occur de novo with no identifiable cause. Although the bone marrow is usually hypercellular at diagnosis, 10% of patients present with a hypoplastic bone marrow. Single-nucleotide polymorphism array technology may increase the detection of genetic abnormalities to 80%. Approximately 50% of patients have a detectable cytogenetic abnormality, most commonly a deletion of all or part of chromosome 5 or 7, or trisomy 8. Splenomegaly or hepatosplenomegaly may indicate an overlapping myeloproliferative neoplasm. Anemia, bleeding, easy bruising, and fatigue are common initial findings. MDS occur predominantly in older patients (usually older than 60 years), with a median age at diagnosis of approximately 70 years, although patients as young as 2 years have been reported. Abnormally small megakaryocytes (micromegakaryocytes) may be seen in the marrow, and hypogranular or giant platelets may appear in the blood. Early, abnormal myeloid progenitors are identified in the marrow in varying percentages. Circulating granulocytes are often hypogranular or hypergranular and may display the acquired pseudo-Pelger-Huët abnormality. Megaloblastoid erythroid hyperplasia with macrocytic anemia, associated with normal vitamin B 12 and folate levels, is frequently observed. MDS are characterized by abnormal bone marrow and blood cell morphology. The acute leukemic phase is less responsive to chemotherapy than is de novo AML. For more information, see the Pathological and Prognostic Systems for MDS section. ![]() Many patients succumb to complications of cytopenias before progression to this stage. By convention, MDS are reclassified as acute myeloid leukemia (AML) with myelodysplastic features when blood or bone marrow blasts reach or exceed 20%. Prognosis is directly related to the number of bone marrow blast cells, to certain cytogenetic abnormalities, and to the amount of peripheral blood cytopenias. The syndromes may arise de novo or secondarily after treatment with chemotherapy and/or radiation therapy for other cancers or, rarely, after environmental exposures. They are more common in men and White individuals. MDS are diagnosed in slightly more than 10,000 people in the United States yearly, for an annual age-adjusted incidence rate of approximately 4.4 to 4.6 cases per 100,000 people. ![]() The MDS are a collection of myeloid malignancies characterized by one or more peripheral blood cytopenias. General Information About Myelodysplastic Syndromes (MDS) ![]()
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