Myelodysplastic syndrome (MDS) is a hematopoietic stem cell disease, resulting in uni- or multilineage cytopenia, dysplasia and an increased risk of transformation into acute myeloid leukemia (AML). MDS is a rare disease in children.
The low-grade variant 'refractory cytopenia of childhood' (RCC), defined as myelodysplasia without an increased blast count, is the most common subtype of MDS accounting for half of all paediatric MDS cases. RCC is often hard to diagnose, especially when karyotype and molecular mutation screening do not show any abnormality, as over two-third of the patients with RCC show a reduced bone marrow cellularity.