ICD-10 Code C77 – Secondary and unspecified malignant neoplasm of lymph nodes (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C77 – Secondary and unspecified malignant neoplasm of lymph nodes
What it is
C77 identifies metastatic cancer involving lymph nodes, or a lymph node malignancy that is not further specified. Use it when the record shows secondary spread to lymph nodes rather than a primary lymph node cancer.
Clinical signs
Findings may include enlarged or firm lymph nodes on exam or imaging, often in a patient with known cancer. Clinical features vary; refer to documentation.
When to use this code
Use C77 when the provider documents lymph node metastasis from another primary site, such as regional or distant nodal spread. It also applies when the chart states malignant lymph node involvement without a more specific site. You should code the documented primary malignancy separately when available.
Do not use for
Do not use C77 for primary lymphoma or leukemia, which are coded elsewhere. Do not use it when lymphadenopathy is nonmalignant or when the record does not confirm cancer involvement; check documentation.
Coding tip
Verify whether the lymph node disease is secondary or primary, and capture the primary cancer code whenever the documentation supports it.