Refractory cytopenias with unilineage dysplasia (RCUD) is a frequent low-risk subtype of myelodysplastic syndrome (MDS; see this term) characterized by refractory cytopenias associated with dysplasia limited to one cell lineage.

A compact, organized collection of mature mononuclear phagocytes, which may be but is not necessarily accompanied by accessory features such as necrosis.