Search Database ICD-O-3 Code Lists

Name

Myelodysplastic/myeloproliferative neoplasm, NOS, unclassifiable (MPN/MDS-U)

ICD-O-3 Morphology

9975/3: Myelodysplastic/myeloproliferative neoplasm, unclassifiable
Effective 2001 and later

Reportable

for cases diagnosed 1992 and later

Primary Site(s)

C421
Primary site must be bone marrow (C421). Blood and bone marrow are the major sites of involvement. In advanced stages, the spleen and liver may also be affected.

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

Myelodysplastic/myeloproliferative neoplasm, NOS, unclassifiable (MPN/MDS-U) 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)

This diagnosis is one of exclusion.

In patients with MPNs that are initially unclassifiable, follow-up studies performed at intervals of 6-12 months can often provide sufficient information for a more precise classification. If a more specific MPN is diagnosed, change the ICD-O-3 histology code to the more specific MPN. Do not abstract a new primary.

Specific myeloproliferative neoplasms (MPN) include:
1. Chronic eosinophilic leukemia, NOS (9964/3)
2. Chronic myelogenous leukemia BCR-ABL1-positive (9875/3)
3. Chronic neutrophilic leukemia (9963/3)
4. Essential thrombocythemia (9962/3)
5. Polycythemia vera (9950/3)
6. Primary myelofibrosis (9961/3)

Specific myelodysplastic/myeloproliferative neoplasms include (MDS/MPN):
1. Atypical chronic myeloid leukemia BCR-ABL1-negative (9876/3)
2. Chronic myelomonocytic leukemia (9945/3)
3. Juvenile myelomonocytic leukemia (9946/3)
4. Myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (9982/3)

Diagnostic Confirmation

This is a histology for which the Definitive Diagnostic Method does not include Genetics Data or Immunophenotyping, thus Diagnostic Confirmation should never be 3. If genetics and/or immunophenotyping are available, re-review to see if a more specific neoplasm can be coded.

Module Rule

None

Alternate Names

Chronic myeloproliferative disease, NOS (CMD) (see 9960/3 prior to 2010)
Chronic myeloproliferative disorder (see 9960/3 prior to 2010)
Chronic myeloproliferative neoplasm
Chronic myelodysplastic/myeloproliferative disease, unclassifiable (CMPD-U)
Myeloid neoplasm, NOS
Myeloproliferative disease, NOS (see 9960/3 prior to 2010)
Myeloproliferative disorder, NOS
Myeloproliferative syndrome [OBS]
Undifferentiated myeloproliferative disease
Myeloproliferative neoplasm, NOS, unclassifiable (MPN-U) (see 9960/3 prior to 2010)

Definition

Myeloproliferative neoplasm (MPN) not otherwise specified (NOS) is a diagnosis of exclusion for cases that have definite clinical, laboratory, morphological, and molecular features of an MPN but fail to meet the diagnostic criteria for any of the specific types in this disease category. (WHO 5th edition)

Most cases that are diagnosed as MPN-NOS constitute very early-stage disease, in which the differentiation between essential thrombocythemia, primary myelofibrosis (PMF), and polycythemia vera may be very difficult.

In late-stage disease, bone marrow specimens may show dense fibrosis and/or osteosclerosis, indicating a terminal burnt-out stage; every possible effort should be made to identify the specific type of MPN.

Definitive Diagnostic Methods

Clinical diagnosis
Histologic confirmation

Genetics Data

None

Immunophenotyping

None

Treatments

Chemotherapy

Transformations to

Transformations from

None

Same Primaries

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

D47.1 Chronic myeloproliferative disease

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

D47.1 Chronic myeloproliferative disease (effective October 01, 2015)
C94.6 Myelodysplastic disease, not elsewhere classified (effective October 01, 2015)

Signs and Symptoms

Easy bruising or bleeding
Fatigue
Fever
Frequent infections
Pain or a feeling of fullness below the rib
Pale skin
Petechiae
Shortness of breath
Weakness
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

None

Epidemiology and Mortality

Incidence: ~10-15% of all cases of MPN
Survival: Depends on what stage diagnosed at. Early stage MPN will have the same survival as some of the more specified MPN's, while late stage has a poor prognosis

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: Myeloproliferative neoplasms
Pages: Part A: 57-59

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 <02/05/2025>. [PMID: 26389321]
Section: Myelodysplastic/Myeloproliferative Neoplasms Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/myeloproliferative/hp/mds-mpd-treatment-pdq
Glossary