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Name
Leukemia, NOS
Effective
1978 - 1991
Effective
1992 - 2000
ICD-O-3 Morphology
9800/3: Leukemia, NOS
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
Leukemia, NOS is a generic neoplasm description. DCO cases or path report only cases may stay in this classification.
In most cases, NOS histology is only the provisional diagnosis; the physician will run further diagnostic procedures and look for various clinical presentations to identify a more specific leukemia. Further review of the medical record should be done to look for immunophenotyping or genetic testing that would lead to a more specific diagnosis. If the information is not available in the medical record, follow-back with the treating physician.
A more specific diagnosis would include acute leukemia, NOS as well as any specific acute or chronic leukemia. When a more specific diagnosis is identified, the histology should be changed to the more specific neoplasm name and code. See the histology tables for more information on NOS and more specific histologies.
In most cases, NOS histology is only the provisional diagnosis; the physician will run further diagnostic procedures and look for various clinical presentations to identify a more specific leukemia. Further review of the medical record should be done to look for immunophenotyping or genetic testing that would lead to a more specific diagnosis. If the information is not available in the medical record, follow-back with the treating physician.
A more specific diagnosis would include acute leukemia, NOS as well as any specific acute or chronic leukemia. When a more specific diagnosis is identified, the histology should be changed to the more specific neoplasm name and code. See the histology tables for more information on NOS and more specific histologies.
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.
Grade
Not Applicable
Module Rule
None
Alternate Names
Definition
Leukemia is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). This is a general term for leukemia (unknown cell type, unknown if acute or chronic).
Definitive Diagnostic Methods
None
Genetics Data
None
Immunophenotyping
None
Treatments
None
Transformations to
There are no known transformations
Transformations from
There are no known transformations
Same Primaries
Corresponding ICD-9 Codes
208.9 Unspecified leukemia
208.1 Chronic leukemia
208.2 Subacute leukemia
208.8 Other leukemia of unspecified cell type
Corresponding ICD-10 Codes
C95.9 Leukemia, unspecified
C95.1 Chronic leukemia of unspecified cell type
C95.2 Subacute leukemia of unspecified cell type
C95.7 Other leukemia of unspecified cell type
Corresponding ICD-10-CM Codes (U.S. only)
C95.9 Leukemia, unspecified (effective October 01, 2015)
C95.1 Chronic leukemia of unspecified cell type (effective October 01, 2015)
Signs and Symptoms
None
Diagnostic Exams
None
Progression and Transformation
None
Epidemiology and Mortality
None
Sources
International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 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
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
