C77.0
BillableSecondary and unspecified malignant neoplasm of lymph nodes of head, face and neck
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C77.0 an HCC code?
Yes. C77.0 maps to Metastatic Cancer to Peritoneum and Other Specified Sites under the CMS-HCC V28 risk adjustment model (and Metastatic Cancer and Acute Leukemia under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for C77.0
For C77.0 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C77.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C77.0 is the ICD-10-CM diagnosis code for secondary and unspecified malignant neoplasm of lymph nodes of head, face and neck. Cancer that has spread to or originated in the lymph nodes of the head, face, and neck region. C77.0 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).
Under the CMS-HCC V28 risk adjustment model, C77.0 maps to Metastatic Cancer to Peritoneum and Other Specified Sites (HCC 18) with a community, non-dual, aged base RAF weight of 0.368. Under the older CMS-HCC V24 model, C77.0 maps to Metastatic Cancer and Acute Leukemia (HCC 8) with a community, non-dual, aged base RAF weight of 2.484. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This code includes both secondary (metastatic) cancers and primary lymph node malignancies in this region. Because C77.0 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C77.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code includes both secondary (metastatic) cancers and primary lymph node malignancies in this region
- •Specify the primary cancer site separately if known, as this code focuses on lymph node involvement
Clinical Significance
Secondary and unspecified malignant neoplasm of lymph nodes of the head, face, and neck is a high-impact code representing metastatic cancer involving cervical, facial, or occipital lymph nodes. Cervical lymph node metastasis is a common presentation of head and neck squamous cell carcinoma, thyroid cancer, and cancers of unknown primary. This code carries one of the highest RAF weights in the cancer HCC categories.
Documentation Requirements
- ✓Pathology or imaging confirming malignant lymphadenopathy in the head, face, or neck region
- ✓Identification of the primary malignancy site — code the primary tumor separately
- ✓Specific lymph node stations involved (cervical levels I-V, submandibular, parotid, occipital)
- ✓Documentation of whether this represents recurrent/progressive disease or initial presentation
- ✓Treatment plan addressing both the primary and metastatic disease