An official website of the United States government
Home
This neoplasm is not reportable.
Name
Clonal hematopoiesis (CH)
ICD-O-3 Morphology
9860/0
Effective
2026 and later
Reportability
This neoplasm is not reportable
Primary Site(s)
No primary site specified
Primary site bone marrow (C421)
This hematopoietic disease is not reportable for the U.S.
Canada, refer to your specific province for reportability requirements.
This hematopoietic disease is not reportable for the U.S.
Canada, refer to your specific province for reportability requirements.
Abstractor Notes
Clonal hematopoiesis is part of the Myeloid precursor lesions lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B1)
CH is nearly always an incidental finding without associated clinical features. The absence of histopathological features of defined myeloid neoplasms is integral to the definition of CH.
CHIP is recognized as a precursor state that is distinct from hematological neoplasms and has a predominantly benign natural history.
Bone marrow evaluation of patients with VEXAS syndrome shows cytoplasmic vacuoles in myeloid and erythroid precursors. Other findings include hypercellularity, usually without dysplasia.
Progression to a myeloid neoplasm, particularly MDS, increases with the size of the clonal population.
- If a patient with history of CH progresses to MDS, the MDS is the first primary.
CH is nearly always an incidental finding without associated clinical features. The absence of histopathological features of defined myeloid neoplasms is integral to the definition of CH.
CHIP is recognized as a precursor state that is distinct from hematological neoplasms and has a predominantly benign natural history.
Bone marrow evaluation of patients with VEXAS syndrome shows cytoplasmic vacuoles in myeloid and erythroid precursors. Other findings include hypercellularity, usually without dysplasia.
Progression to a myeloid neoplasm, particularly MDS, increases with the size of the clonal population.
- If a patient with history of CH progresses to MDS, the MDS is the first primary.
Alternate Names
Age-related clonal hematopoiesis (ARCH)
Clonal hematopoiesis of indeterminate potential (CHIP)
VEXAS syndrome
Definition
"Clonal haematopoiesis (CH) in the context of ageing refers to the presence of a population of cells derived from a multipotent stem/progenitor cell harbouring one or more driver gene mutations resulting in selective growth advantage in individuals without unexplained cytopenias, haematological cancers, or other clonal disorders." (WHO 5th edition)
"Clonal cytopenia of undetermined significance (CCUS) refers to clonal haematopoiesis (CH) detected in the presence of one or more persistent cytopenias that are otherwise unexplained by haematological or non-haematological conditions." (WHO 5th edition)
"Clonal cytopenia of undetermined significance (CCUS) refers to clonal haematopoiesis (CH) detected in the presence of one or more persistent cytopenias that are otherwise unexplained by haematological or non-haematological conditions." (WHO 5th edition)
Epidemiology and Mortality
Rare in individuals less than 40 years of age
Increases steadily in incidence in those 65 and older, affects 10-40% of elderly individuals
Sources
WHO Classification of Tumours Editorial Board. Haematolymphoid tumours. Lyon (France): International Agency for Research on Cancer; 2024. (WHO classification of tumours series, 5th ed.; vol. 11). https://publications.iarc.who.int/637.
Section: Myeloid precursor lesions
Pages: Part A: 19-23
Section: Myeloid precursor lesions
Pages: Part A: 19-23
