2021 ICD-10-CM Diagnosis Code C94.3

Mast cell leukemia

    2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
  • C94.3 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2021 edition of ICD-10-CM C94.3 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of C94.3 - other international versions of ICD-10 C94.3 may differ.
The following code(s) above C94.3 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to C94.3:
  • C00-D49
    2021 ICD-10-CM Range C00-D49


    • Functional activity
    • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
    • Morphology [Histology]
    • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
    • Primary malignant neoplasms overlapping site boundaries
    • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
    • Malignant neoplasm of ectopic tissue
    • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
  • C81-C96
    2021 ICD-10-CM Range C81-C96

    Malignant neoplasms of lymphoid, hematopoietic and related tissue

    Type 2 Excludes
    • Kaposi's sarcoma of lymph nodes (C46.3)
    • secondary and unspecified neoplasm of lymph nodes (C77.-)
    • secondary neoplasm of bone marrow (C79.52)
    • secondary neoplasm of spleen (C78.89)
    Malignant neoplasms of lymphoid, hematopoietic and related tissue
  • C94
    ICD-10-CM Diagnosis Code C94

    Other leukemias of specified cell type

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • leukemic reticuloendotheliosis (C91.4-)
    • myelodysplastic syndromes (D46.-)
    • personal history of leukemia (Z85.6)
    • plasma cell leukemia (C90.1-)
    Other leukemias of specified cell type
Clinical Information
  • A form of systemic mastocytosis (mastocytosis, systemic) characterized by the presence of large numbers of tissue mast cells in the peripheral blood without skin lesions. It is a high-grade leukemia disease with bone marrow smear of >20% mast cells, multi-organ failure and a short survival.
  • A variant of systemic mastocytosis with involvement of the bone marrow (20% or more mast cells) and the peripheral blood (mast cells account for 10% or more of peripheral blood white cells). (who, 2001)
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
Code annotations containing back-references to C94.3:
  • Type 1 Excludes: D47.02
    , D89.4
    ICD-10-CM Diagnosis Code D47.02

    Systemic mastocytosis

      2018 - New Code 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Indolent systemic mastocytosis
    • Isolated bone marrow mastocytosis
    • Smoldering systemic mastocytosis
    • Systemic mastocytosis, with an associated hematological non-mast cell lineage disease (SM-AHNMD)
    Code Also
    • , if applicable, any associated hematological non-mast cell lineage disease, such as:
    • acute myeloid leukemia (C92.6-, C92.A-)
    • chronic myelomonocytic leukemia (C93.1-)
    • essential thrombocytosis (D47.3)
    • hypereosinophilic syndrome (D72.1)
    • myelodysplastic syndrome (D46.9)
    • myeloproliferative syndrome (D47.1)
    • non-Hodgkin lymphoma (C82-C85)
    • plasma cell myeloma (C90.0-)
    • polycythemia vera (D45)
    Type 1 Excludes
    • aggressive systemic mastocytosis (C96.21)
    • mast cell leukemia (C94.3-)
    ICD-10-CM Diagnosis Code D89.4

    Mast cell activation syndrome and related disorders

      2017 - New Code 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • aggressive systemic mastocytosis (C96.21)
    • congenital cutaneous mastocytosis (Q82.2)
    • (non-congenital) cutaneous mastocytosis (D47.01)
    • (indolent) systemic mastocytosis (D47.02)
    • malignant mast cell neoplasm (C96.2-)
    • malignant mastocytoma (C96.29)
    • mast cell leukemia (C94.3-)
    • mast cell sarcoma (C96.22)
    • mastocytoma NOS (D47.09)
    • other mast cell neoplasms of uncertain behavior (D47.09)
    • systemic mastocytosis associated with a clonal hematologic non-mast cell lineage disease (SM-AHNMD) (D47.02)

Diagnosis Index entries containing back-references to C94.3:
  • Leukemia, leukemic C95.9-
    ICD-10-CM Diagnosis Code C95.9-

    Leukemia, unspecified

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    • mast cell C94.3-
  • Mast cell
    • leukemia C94.3-

ICD-10-CM Codes Adjacent To C94.3
C93.92 …… in relapse
C94 Other leukemias of specified cell type
C94.0 Acute erythroid leukemia
C94.00 …… not having achieved remission
C94.01 …… in remission
C94.02 …… in relapse
C94.2 Acute megakaryoblastic leukemia
C94.20 …… not having achieved remission
C94.21 …… in remission
C94.22 …… in relapse
C94.3 Mast cell leukemia
C94.30 …… not having achieved remission
C94.31 …… in remission
C94.32 …… in relapse
C94.4 Acute panmyelosis with myelofibrosis
C94.40 …… not having achieved remission
C94.41 …… in remission
C94.42 …… in relapse
C94.6 Myelodysplastic disease, not classified
C94.8 Other specified leukemias
C94.80 …… not having achieved remission

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.