2026 ICD-10-CM Diagnosis Code C79Secondary malignant neoplasm of other and unspecified sites

ICD-10-CM Codes›C00–D49›C76-C80›C79

ICD-10-CM C79
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C79 is a non-billable ICD-10-CM category code for secondary malignant neoplasm of other and unspecified sites, so it cannot be submitted on claims. Use a more specific code from this category instead, such as C79.00, C79.01, C79.02, and C79.10.

Code Identity

ICD-10-CM Code
C79
Billable Status
No — Non-Billable Category
Code Describes
Secondary malignant neoplasm of other and unspecified sites
Short Description
Secondary malignant neoplasm of other and unspecified sites
Same as the full description in the CMS dataset.
Chapter
C76-C80
Malignant neoplasms of ill-defined, other secondary and unspecified sites

Code Classification

ChapterC00–D49Neoplasms
SectionC76-C80Malignant neoplasms of ill-defined, other secondary and unspecified sites
CategoryC79Secondary malignant neoplasm of other and unspecified sites
This CodeC79Secondary malignant neoplasm of other and unspecified sites

Specific Coding for Secondary malignant neoplasm of other and unspecified sitesOverview

Non-specific codes like C79 require more characters. Use one of these billable codes instead:

  • C79.0 for Secondary malignant neoplasm of kidney and renal pelvis

  • Use C79.00 for Secondary malignant neoplasm of unspecified kidney and renal pelvis

  • Use C79.01 for Secondary malignant neoplasm of right kidney and renal pelvis

  • Use C79.02 for Secondary malignant neoplasm of left kidney and renal pelvis

  • C79.1 for Secondary malignant neoplasm of bladder and other and unspecified urinary organs

  • Use C79.10 for Secondary malignant neoplasm of unspecified urinary organs

  • Use C79.11 for Secondary malignant neoplasm of bladder

  • Use C79.19 for Secondary malignant neoplasm of other urinary organs

  • Use C79.2 for Secondary malignant neoplasm of skin

  • C79.3 for Secondary malignant neoplasm of brain and cerebral meninges

  • Use C79.31 for Secondary malignant neoplasm of brain

  • Use C79.32 for Secondary malignant neoplasm of cerebral meninges

  • C79.4 for Secondary malignant neoplasm of other and unspecified parts of nervous system

  • Use C79.40 for Secondary malignant neoplasm of unspecified part of nervous system

  • Use C79.49 for Secondary malignant neoplasm of other parts of nervous system

  • C79.5 for Secondary malignant neoplasm of bone and bone marrow

  • Use C79.51 for Secondary malignant neoplasm of bone

  • Use C79.52 for Secondary malignant neoplasm of bone marrow

  • C79.6 for Secondary malignant neoplasm of ovary

  • Use C79.60 for Secondary malignant neoplasm of unspecified ovary

  • Use C79.61 for Secondary malignant neoplasm of right ovary

  • Use C79.62 for Secondary malignant neoplasm of left ovary

  • Use C79.63 for Secondary malignant neoplasm of bilateral ovaries

  • C79.7 for Secondary malignant neoplasm of adrenal gland

  • Use C79.70 for Secondary malignant neoplasm of unspecified adrenal gland

  • Use C79.71 for Secondary malignant neoplasm of right adrenal gland

  • Use C79.72 for Secondary malignant neoplasm of left adrenal gland

  • C79.8 for Secondary malignant neoplasm of other specified sites

  • Use C79.81 for Secondary malignant neoplasm of breast

  • Use C79.82 for Secondary malignant neoplasm of genital organs

  • Use C79.89 for Secondary malignant neoplasm of other specified sites

  • Use C79.9 for Secondary malignant neoplasm of unspecified site

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • secondary carcinoid tumors C7B
  • secondary neuroendocrine tumors C7B

Patient EducationClinical

Cancer

Cancer is not just one disease but many diseases. Cancer begins in your cells, which are the building blocks of your body. Usually, your body forms new cells as needed, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should.

The full article covers:

  • What is cancer?
  • What are the types of cancer?
  • How does cancer develop?
  • What are the symptoms of cancer?
  • How is cancer diagnosed?
  • What are the treatments for cancer?
  • Can cancer be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C79Overview

Is C79 (Secondary malignant neoplasm of other and unspecified sites) a billable code?

No. This is a category header that groups the codes for secondary malignant neoplasm of other and unspecified sites, and headers cannot be submitted on claims. Claims for secondary malignant neoplasm of other and unspecified sites need a more specific code from this category, such as C79.00, C79.01, and C79.02.