Morphological findings in myelodysplasic syndromes

Hallazgos morfológicos en síndromes mielodisplásicos

Myelodysplastic Syndromes (MDS) are a group of diverse clonal hematopoietic disorders manifested by morphologic dysplasia in hematopoietic cells and by bone marrow failure, characterized by ineffective hematopoiesis that generates functional alterations, cytopenias, anemia, recurrent infections, and bleeding. It occurs between 65 and 70-year-old patients, especially those who have comorbidities that decrease the therapeutic response. In 2016 the world health organization classified them as MDS with single lineage dysplasia (MDS-SLD), MDS with ring sideroblasts (MDS-RS), MDS with multilineage dysplasia (MDS-MLD), MDS with excess blasts (MDS-EB) type 1 (MDS-EB-1), and type 2 (MDS-EB-2), MDS with isolated del(5q), MDS unclassifiable (MDS-U), and Refractory cytopenia of childhood (RCC). The diagnosis can be assessed by different methodologies; such as immunophenotype by flow cytometry, cytogenetics, and morphological observation of dysplasia in peripheral blood and bone marrow, which reveal the type of myelodysplasia and the prognosis of the patient. Dysplasia can occur in one or more cell lines, being the most relevant the changes in the nuclei, such as karyorrhexis, internuclear bridging in the erythroid lineage; also abnormal chromatin changes in granulocytes (lobulation, shape, and number alterations), small size, and megaloblastic changes; and in the cytoplasm the presence of iron deposits such as ringed sideroblasts, hypogranulation, aberrant Chediak-type granules, toxic or mixed granulations, and presence of micromegakaryocytes. The morphological changes in the peripheral blood are the first approach to diagnose dysplasia, which is why it is necessary to strengthen the observation of peripheral blood and bone marrow smears in 100X, associated with cell counts, to ensure a timely diagnosis of the Myelodysplastic Syndrome.