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Review
. 2021 Dec 10;2021(1):399-404.
doi: 10.1182/hematology.2021000272.

When are idiopathic and clonal cytopenias of unknown significance (ICUS or CCUS)?

Afaf E W G Osman  1
Affiliations
Review

When are idiopathic and clonal cytopenias of unknown significance (ICUS or CCUS)?

Afaf E W G Osman. Hematology Am Soc Hematol Educ Program. .

Abstract

Rapid advances in sequencing technology have led to the identification of somatic mutations that predispose a significant subset of the aging population to myeloid malignancies. Recently recognized myeloid precursor conditions include clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of unknown significance (CCUS). These conditions can present diagnostic challenges and produce unwarranted anxiety in some instances. While the risk of progression to myeloid malignancies is very low in CHIP, true CCUS confers an exponential increase in risk. Idiopathic cytopenia of unknown significance (IDUS) lacks the predisposing genetic mutations and has a variable course. In this review we define the early myeloid precursor conditions and their risk of progression. We present our diagnostic approach to patients with unexplained cytopenias and discuss the clinical consequences of CHIP and CCUS.

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Conflict of interest statement

Afaf E. W. G. Osman: no competing financial interests to declare.

Figures

None
Graphical abstract
Figure 1.
Figure 1.
The diagnostic workup for cytopenias starts with ruling out underlying etiologies, including nutritional, autoimmune, infectious, drug-mediated, and neoplastic processes. NGS plays an important role in the workup of unexplained cytopenias to differentiate between CCUS and ICUS.
See this image and copyright information in PMC

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