C22.9
BillableMalignant neoplasm of liver, not specified as primary or secondary
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C22.9 an HCC code?
Yes. C22.9 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers 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 C22.9
For C22.9 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 C22.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C22.9 is the ICD-10-CM diagnosis code for malignant neoplasm of liver, not specified as primary or secondary. A liver cancer where it is unclear whether it originated in the liver (primary) or spread to the liver from another location (secondary/metastatic). C22.9 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of digestive organs (c15-c26).
Under the CMS-HCC V28 risk adjustment model, C22.9 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, C22.9 mapped to the same category but with a base RAF weight of 0.973 — 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.
Clarify with provider whether cancer is primary liver cancer or metastatic disease from another site. Because C22.9 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 C22.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Malignant neoplasm of liver, not specified as primary or secondary, represents the least specific liver cancer code and indicates a significant documentation gap. Determining whether liver cancer is primary or secondary (metastatic) is essential because the treatment approach is entirely different — primary liver cancer may require liver-directed therapy or transplantation, while metastatic disease requires treatment of the original primary cancer. This code should trigger a provider query to clarify the nature of the malignancy.
Documentation Requirements
- ✓Confirmation of liver malignancy
- ✓Investigation to determine primary versus secondary status (imaging, biopsy, clinical history)
- ✓Any known history of other cancers that could be the primary source
- ✓Tumor markers (alpha-fetoprotein, carcinoembryonic antigen, cancer antigen 19-9)
- ✓Imaging characteristics that may help distinguish primary from metastatic disease