ICD-10 Code C79.89 – Secondary malignant neoplasm of other specified sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C79.89 – Secondary malignant neoplasm of other specified sites
What it is
This code identifies metastatic cancer found in a site that is not named by a more specific secondary malignancy code. Use it when the chart documents spread of a primary cancer to another specified location.
Clinical signs
Clinical features vary; refer to documentation. You may see imaging, pathology, or operative findings confirming metastatic disease in an identified site, along with a known or suspected primary malignancy.
When to use this code
Use C79.89 when the provider documents secondary malignant involvement of a specific site that does not have its own more precise ICD-10-CM code. It is appropriate when the record clearly states metastasis, secondary cancer, or secondary malignant neoplasm. If the site is not specified, check documentation before assigning this code.
Do not use for
Do not use this code for primary malignancies, benign tumors, or uncertain lesions. Also avoid it when a more specific secondary site code is available or when the documentation only says “metastatic cancer” without a named site.
Coding tip
Match the documented metastatic site exactly and verify whether a more specific secondary neoplasm code applies before defaulting to C79.89.