Idiopathic cytopenia of undetermined significance—ICUS The definition of ICUS is based on unexplained persistent cytopenia, and the failure to establish a diagnosis of MDS by accepted criteria [4] , [6] , [7] , [8] . Blood 2017; 130:742. These patients are now classified as idiopathic cytopenia of undetermined significance (ICUS) or if a mutation is detected as clonal cytopenia of undetermined significance (CCUS). Kwok B, Hall JM, Witte JS, et al. To formulate a diagnosis of ICUS, a thorough diagnostic work-up is required and repeated tests should be performed to reach a … At least in some patients these are neoplastic conditions. The provisional category of idiopathic cytopenia of undetermined significance (ICUS) has been proposed to describe patients in whom MDS is possible but not proven. Zink F, Stacey SN, Norddahl GL, et al. Cytopenia is a hallmark in myelodysplastic syndrome (MDS), however, many patients with persistent cytopenia do not fulfill the criteria for MDS. Clonal hematopoiesis, with and without candidate driver mutations, is common in the elderly. MDS-associated somatic mutations and clonal hematopoiesis are common in idiopathic cytopenias of undetermined significance. cytopenia of undetermined significance (ICUS) and idiopathic bone marrow dysplasia of uncertain significance (IDUS).

Blood 2015; 126:2355. The phrase “idiopathic cytopenia of undetermined significance (ICUS)”, as also suggested by Mufti and co-workers, is proposed and long term follow-up is recommended to assess the evolution… Both conditions may progress to an overt myelodysplastic syndrome (MDS), but may also progress to another myeloid neoplasm such as acute