ICD-10 Code C79.8 – Secondary malignant neoplasm of other specified sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C79.8 – Secondary malignant neoplasm of other specified sites
What it is
This code identifies metastatic cancer found in a site that is not separately named in the ICD-10-CM category. Use it when documentation confirms a secondary malignant deposit, but the exact location is described only as “other specified.”
Clinical signs
Clinical features vary; refer to documentation. Typical findings reflect metastatic disease at the involved site, such as a mass, pain, or organ-specific dysfunction, but the primary cancer should also be documented.
When to use this code
Use C79.8 when the provider states there is secondary malignant neoplasm in a specified site that is not listed by a more precise ICD-10-CM code. It is appropriate when the metastatic location is documented clearly, even if the primary tumor is elsewhere. Check documentation if the record names a more specific metastatic site.
Do not use for
Do not use this code for the primary malignancy or for metastatic sites that have their own specific ICD-10-CM code. If the chart only says “metastatic cancer” without a site, check documentation.
Coding tip
Code the primary cancer first when required, and confirm the metastatic site is truly “other specified” before assigning C79.8.