C77.8
BillableSecondary and unspecified malignant neoplasm of lymph nodes of multiple regions
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C77.8 an HCC code?
Yes. C77.8 maps to Metastatic Cancer and Acute Leukemia 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 C77.8
For C77.8 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 C77.8 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C77.8 is the ICD-10-CM diagnosis code for secondary and unspecified malignant neoplasm of lymph nodes of multiple regions. Cancer that has spread to lymph nodes in multiple different regions of the body, either as a secondary spread from another cancer or when the primary source is unknown. C77.8 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, C77.8 maps to Metastatic Cancer and Acute Leukemia (HCC 17) with a community, non-dual, aged base RAF weight of 0.368. Under the older V24 model, C77.8 mapped to the same category but with a base RAF weight of 2.484 — V28 recalibrated weights across the entire model. 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.
Use this code only when lymph node involvement is documented in multiple non-contiguous regions; if involvement is in a single region, use the specific regional code. Because C77.8 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 C77.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when lymph node involvement is documented in multiple non-contiguous regions; if involvement is in a single region, use the specific regional code
- •Always attempt to identify and code the primary malignancy separately when possible
Clinical Significance
Secondary and unspecified malignant neoplasm of lymph nodes of multiple regions indicates metastatic cancer has spread to lymph node groups in more than one anatomical region. This represents advanced metastatic disease and is a significant prognostic indicator. When multiple lymph node regions are involved, it often signifies widespread dissemination and impacts staging and treatment decisions profoundly.
Documentation Requirements
- ✓Documentation specifying which multiple lymph node regions are involved
- ✓Consider coding each regional lymph node group separately instead of using this combined code
- ✓Pathology or imaging confirming malignant lymphadenopathy in multiple regions
- ✓Identification and separate coding of the primary malignancy
- ✓Staging assessment reflecting multi-regional nodal involvement