Myelodysplastic/myeloproliferative neoplasm, unclassifiable

ICD-O-1 Morphology

9960/1: Chronic myeloproliferative disease
Effective 1978 - 1991

ICD-O-2 Morphology

9960/1: Chronic myeloproliferative disease
Effective 1992 - 2000

ICD-O-3 Morphology

9975/3: Myelodysplastic/myeloproliferative neoplasm, unclassifiable
Effective 2010 and later


for cases diagnosed 2010 and later

Primary Site(s)

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

Abstractor Notes

(This neoplasm is reportable for cases diagnosed 2010 and later.)

For cases prior to 2010, Chronic myeloproliferative disease, NOS (9960/3) was used for the generic description.

For cases diagnosed 2010+, code 9975/3 is used for MPN, NOS as well as a new NOS for myeloproliferative neoplasm, unclassifiable and myelodysplastic/myeloproliferative syndrome unclassifiable (MPN, U) that became effective for cases diagnosed 1/1/2010.

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.

Aspirin was previously documented as treatment for MPN, NOS. This was found to be incorrect. Treatment has been updated based on the NCI website. Aspirin is given to patients with MPN, NOS to reduce risk of blood clots. The aspirin is not used to manage the cancer. Treatment has been updated based on the NCI website (updated 6/12/15).

For more information, see the NCI website:

Diagnostic Confirmation

This histology can be determined by positive histology (including peripheral blood) with or without genetics and/or immunophenotyping. Review the Definitive Diagnostic Methods, Immunophenotyping and Genetics Data sections below, and the instructions in the Hematopoietic Manual for further guidance on assigning Diagnostic confirmation.


Not Applicable

Module Rule


Alternate Names

Chronic myelodysplastic/myeloproliferative disease
Chronic myeloproliferative disease
Chronic myeloproliferative disorder
Chronic myeloproliferative neoplasm
Mixed myeloproliferative/myelodysplastic syndrome, unclassifiable
Myelodysplastic/myeloproliferative neoplasm, unclassifiable
Myeloid neoplasm, NOS
Myeloproliferative disease, NOS
Myeloproliferative disorder, NOS
Myeloproliferative neoplasm, unclassifiable
Myeloproliferative syndrome [OBS]
Overlap syndrome, unclassifiable
Undifferentiated myeloproliferative disease


The designation of myeloproliferative neoplasm, unclassifiable (MPN-U) should be applied only to cases that have definite clinical, laboratory, molecular, and morphological features of a myeloproliferative neoplasm (MPN) but fail to meet the diagnostic criteria for any of the specific MPN entities, or that present with features that overlap between two or more of the MPN categories.

In early unclassifiable disease, organomegaly may be minimal or absent, but splenomegaly and hepatomegaly can be massive in advanced cases in which bone marrow specimens are characterized by marked myelofibrosis and/or increased numbers of blasts.

There are three groups of early stage MPN, U:
1) Early stages of polycythemia vera, primary myelofibrosis, or essential thrombocythemia in which the characteristic features are not yet fully developed.

2) Advanced disease in which pronounced myelofibrosis, osteosclerosis, or transformation to a more aggressive stage masks the underlying disorder.

3) Evidence of an MPN where a coexisting neoplastic or inflammatory disorder obscures some of the diagnostic clinical and/or morphologic features.

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)

Definitive Diagnostic Methods

Bone marrow biopsy
Clinical diagnosis

Genetics Data

BCR-ALB1 fusion absent
No rearrangement of PDGFRA, PDGFRB, or FGFR1
PCM1-JAK2 fusion absent





Transformations from


Corresponding ICD-9 Codes

238.79 Other lymphatic and hematopoietic tissues

Corresponding ICD-10 Codes

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 classified (effective October 01, 2015)

Signs and Symptoms

Easy bruising or bleeding
Frequent infections
Pain or a feeling of fullness below the rib
Pale skin
Shortness of breath
Weight loss

Diagnostic Exams

Blood chemistry studies
Cytogenetic analysis
Peripheral blood smear

Progression and Transformation


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


Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Myeloproliferative neoplasms
Pages: 57-59

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes

National Cancer Institute
Section: General Information About Myelodysplastic/Myeloproliferative Neoplasms