[Diagnosis and treatment of childhood myelodysplastic syndrome]

Myelodysplastic syndrome (MDS) is a group of clonal hematopoietic disorders characterized by peripheral cytopenia and morphological abnormalities in hematopoietic cells, i.e., myelodysplasia. Aging-related somatic variants acquired in the hematopoietic cells are associated with MDS pathogenesis in adults. However, pediatric MDS often occurs because of germline predispositions. Myelodysplasia can be observed in not only MDS but also other hematopoietic and non-hematopoietic disorders, such as infections and primary immunodeficiencies. Therefore, careful differential diagnosis between MDS and other diseases is necessary. The bone marrow histopathology should be evaluated for accurate differentiation of MDS without excess blasts from aplastic anemia and MDS with excess blasts from acute myeloid leukemia. The treatment strategy for childhood MDS differs based on disease subtypes. The clinical courses of pediatric MDS without excess blasts are heterogeneous; therefore, it is crucial to assess the prognostic values of clinical and cytogenetic findings. In contrast, allogeneic hematopoietic cell transplantation should be considered as the only curative option for pediatric MDS with excess blasts.