Classic hairy cell leukemia

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Classic hairy cell leukemia

ORPHA:58017Disease

Also called HCL-C · Leukemic reticuloendotheliosis

What it is

A rare, slowly progressive, chronic leukemia characterized by presence of abnormal B-lymphocytes (medium sized with abundant irregular pale cytoplasm, hair-like cytoplasmic projections/ruffled cytoplasmic border, a round or bean-shaped nucleus and absent nucleoli) in the blood or bone marrow, spleen and peripheral blood pancytopenia, notable monocytopenia, and marked susceptibility to infection. The characteristic immunophenotype is CD11c+, CD25+, CD103+ and CD123+ with a BRAF mutation in most cases.

Key facts

Prevalence
1-9 / 100 000 (lifetime, Europe)
Age of onset
Adult
Inheritance
Unknown
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Gene

BRAFDisease-causing somatic mutation(s)

ICD-10 codes

C91.4filed under a broader ICD-10 category — shared with 1 other rare disease

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 6560MEDDRA 10019053MESH D007943MONDO 18935UMLS C0023443

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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