ICD-10 Code C77.9 – Secondary and unspecified malignant neoplasm of lymph node, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C77.9 – Secondary and unspecified malignant neoplasm of lymph node, unspecified
What it is
C77.9 identifies metastatic cancer in a lymph node when the primary site is known or presumed elsewhere, but the specific lymph node region is not documented. Use it for secondary malignant involvement of lymph nodes without further detail.
Clinical signs
Clinical features vary; refer to documentation. Typical records may note enlarged lymph nodes, biopsy-proven metastatic disease, or imaging showing nodal spread from a known malignancy.
When to use this code
Use this code when the chart documents secondary malignant neoplasm involving a lymph node and does not specify the nodal region. It also applies when the record confirms metastatic lymph node disease but gives no more precise site. Verify that the diagnosis is secondary, not primary lymphoma.
Do not use for
Do not use it for primary malignant lymphoma or benign/reactive lymphadenopathy. If the documentation names a specific lymph node group, code that more specific site instead of C77.9.
Coding tip
Code the primary cancer first when documented, and use C77.9 only when the lymph node site is secondary and unspecified.