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Name
Acute undifferentiated leukemia
ICD-O-1 Morphology
Effective
1978 - 1991
ICD-O-2 Morphology
Effective
1992 - 2000
ICD-O-3 Morphology
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
Historically the description for this code has been Acute leukemia, NOS. In the 2008 WHO classification, the definition was changed to acute undifferentiated leukemia.
Acute leukemia NOS is a generic disease description. DCO cases or path report only cases may stay in this classification. In most cases, leukemia, NOS is only the provisional diagnosis; the physician will run further diagnostic procedures and look for various clinical presentations to identify a more specific disease.
Further review of the medical record should be done to look for the tests listed as definitive diagnosis. If no information is found on the medical record, follow-back with the attending physician must be done. The more specific leukemias are any of the specific acute leukemias. 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.
Acute undifferentiated leukemia affects the bone marrow and peripheral blood. There are too few cases to know whether there is a predilection for other sites. These leukemias are very rare and nothing substantial is known about their frequency. While anecdotal experience generally considers these leukemias to be of poor prognosis, information is too scanty to make any definitive statements.
Acute leukemia NOS is a generic disease description. DCO cases or path report only cases may stay in this classification. In most cases, leukemia, NOS is only the provisional diagnosis; the physician will run further diagnostic procedures and look for various clinical presentations to identify a more specific disease.
Further review of the medical record should be done to look for the tests listed as definitive diagnosis. If no information is found on the medical record, follow-back with the attending physician must be done. The more specific leukemias are any of the specific acute leukemias. 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.
Acute undifferentiated leukemia affects the bone marrow and peripheral blood. There are too few cases to know whether there is a predilection for other sites. These leukemias are very rare and nothing substantial is known about their frequency. While anecdotal experience generally considers these leukemias to be of poor prognosis, information is too scanty to make any definitive statements.
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.
Grade
Not Applicable
Module Rule
See abstractor notes
Alternate Names
Definition
Acute undifferentiated leukemia expresses no markers that are specific for either lymphoid or myeloid lineage. Before categorizing a leukemia as undifferentiated, it is necessary to perform immunophenotyping with a comprehensive panel of monoclonal antibodies in order to exclude leukemias of unusual lineages.
Definitive Diagnostic Methods
Bone marrow biopsy
Clinical diagnosis
Immunophenotyping
Peripheral blood smear
Genetics Data
None
Immunophenotyping
CD34 weakly expressed or positive
CD38 expression
HLA-DR expression
TdT positive
Treatments
Chemotherapy
Hematologic Transplant and/or Endocrine Procedures
Transformations to
There are no known transformations
Transformations from
There are no known transformations
Same Primaries
Corresponding ICD-9 Codes
208.0 Acute leukemia of unspecified cell type
Corresponding ICD-10 Codes
C95.0 Acute leukemia of unspecified cell type
Corresponding ICD-10-CM Codes (U.S. only)
C95.0 Acute leukemia of unspecified cell type (effective October 01, 2015)
Signs and Symptoms
Diagnostic Exams
Progression and Transformation
None
Epidemiology and Mortality
None
Sources
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: Acute leukemias of ambiguous terminology
Pages: 182
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Acute leukemias of ambiguous terminology
Pages: 182
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
