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ICD-10-CM 2027 diagnosis code

C79Secondary malignant neoplasm of other and unspecified sites

Not billable — use a more specific code

C79 is a header code, so it can't be reported by itself. Choose one of the 10 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About C79

C79 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of other and unspecified sites. It belongs to block C76-C80 (malignant neoplasms of ill-defined, other secondary and unspecified sites) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 10 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: C79.0 (pelvis), C79.1 (organs), C79.2 (skin), C79.3 (meninges), C79.4 (system), C79.5 (marrow), C79.6 (ovary), C79.7 (gland) and 2 more.

Don't report C79 together with the conditions in its Excludes1 note: secondary carcinoid tumors (C7B.-) and secondary neuroendocrine tumors (C7B.-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under C79

Coding notes

Excludes1Not coded here — never report together with this code
  • secondary carcinoid tumors (C7B.-)
  • secondary neuroendocrine tumors (C7B.-)

Notes that apply from higher levels

Instructions written at a parent level also apply to C79.

Broader instructions also apply from Chapter 2: Neoplasms.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about C79

Is C79 billable?

No. C79 is a header code. Report one of its more specific subcodes instead.