Search Database ICD-O-3 Code Lists

Name

Chronic myelomonocytic leukemia, NOS (CMML) (ICD-O-4: 99450/3)

ICD-O-3 Morphology

9945/3: Chronic myelomonocytic leukemia
Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

C421
Primary site must be bone marrow (C421)

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

Chronic myelomonocytic leukemia, NOS (CMML) is part of the Myelodysplastic/myeloproliferative (MDS/MPN) lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B5)

The peripheral blood and bone marrow are always involved. The spleen, liver, skin and lymph nodes are the most common sites of extramedullary infiltration. The peripheral blood has persistent monocytosis.

Mutations impacting one or more of the cellular processes listed in the genetics section occur in ~92% of cases with CMML.

Diagnostic Confirmation

Assign code 1 for histological confirmation WITH or WITHOUT positive immunophenotyping or genetics

Module Rule

None

Alternate Names

Chronic myelomonocytic leukemia, Type I (CMML-1) (ICD-O-4: 99451/3)
Chronic myelomonocytic leukemia, Type II (CMML-2) (ICD-O-4: 99452/3)
Myelodysplastic chronic myelomonocytic leukemia (MD-CMML) (ICD-O-4: 99453/3)
Myeloproliferative chronic myelomonocytic leukemia (MP-CMML) (ICD-O-4: 99454/3)

Definition

Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm with myelodysplastic and myeloproliferative features, characterized by sustained peripheral blood monocytosis and various combinations of somatic mutations involving epigenetic regulation, spliceosome, and signal transduction genes. (WHO 5th edition)

Nodules of mature plasmacytoid dendritic cell (pDC) proliferations can be detected in the bone marrow and extramedullary sites, particularly in the skin.

Definitive Diagnostic Methods

Cytogenetics
Clinical diagnosis
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

ASXL1, RUNX1, TET2

Immunophenotyping

CD4, CD11c, CD14, CD64, CD68, CD117, CD163, IRF8, lysozyme, NSE

Treatments

Chemotherapy
Hematologic Transplant and/or Endocrine Procedures

Transformations to

Transformations from

None

Same Primaries

Corresponding ICD-10 Codes (Cause of Death codes only)

C93.1 Chronic monocytic leukemia

Corresponding ICD-10-CM Codes (U.S. only)

C93.1 Chronic myelomonocytic leukemia (effective October 01, 2015 - September 30, 2024)
C93.10 Chronic myelomonocytic leukemia not having achieved remission (effective October 01, 2024)
C93.11 Chronic myelomonocytic leukemia, in remission (effective October 01, 2024)
C93.12 Chronic myelomonocytic leukemia, in relapse (effective October 01, 2024)

Signs and Symptoms

Fatigue
Fever
Hepatomegaly
Increased white blood count (WBC) (in some cases)
Leukocytosis
Night sweats
Splenomegaly
Weight loss

Diagnostic Exams

Bone marrow aspiration and biopsy
CT (CAT) scan
Cytogenetic analysis
Flow cytometry
Immunophenotyping
Lumbar puncture
Molecular analysis
Peripheral blood smear
Physical exam and history

Progression and Transformation

Transformation to AML occurs in ~15-30% of cases

Epidemiology and Mortality

Age: 65-75 years median age
Incidence: 0.35 cases per 100,000 per year
Sex: male predominance
Survival: 20-40 months median survival

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: Myelodysplastic/myeloproliferative neoplasms
Pages: Part A: 96-101

International Classification of Diseases for Oncology, 3rd edition (including revisions). Geneva: World Health Organization, 2001, 2011, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577

PDQ® Adult Treatment Editorial Board. PDQ Myelodysplastic/Myeloproliferative Neoplasms Treatment. Bethesda, MD: National Cancer Institute. Updated <06/14/2024>. Available at: https://www.cancer.gov/types/myeloproliferative/hp/mds-mpd-treatment-pdq. Accessed <02/06/2025>. [PMID: 26389321]
Section: Myelodysplastic/Myeloproliferative Neoplasms Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/myeloproliferative/hp/mds-mpd-treatment-pdq
Glossary