C76.8
BillableMalignant neoplasm of other specified ill-defined sites
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C76.8 an HCC code?
Yes. C76.8 maps to Melanoma and Other Skin Cancers under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors 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 C76.8
For C76.8 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 C76.8 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C76.8 is the ICD-10-CM diagnosis code for malignant neoplasm of other specified ill-defined sites. Cancer that has developed in body locations that are not well-defined or do not fit into other specific categories. C76.8 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, C76.8 maps to Melanoma and Other Skin Cancers (HCC 23) with a community, non-dual, aged base RAF weight of 0.251. Under the older CMS-HCC V24 model, C76.8 maps to Breast, Prostate, and Other Cancers and Tumors (HCC 12) with a community, non-dual, aged base RAF weight of 0.150. 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 the cancer site is poorly defined or documented in an unusual location. Because C76.8 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 C76.8 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 the cancer site is poorly defined or documented in an unusual location
- •Review documentation carefully to ensure a more specific site code cannot be assigned
Clinical Significance
Malignant neoplasm of other specified ill-defined sites captures malignancies in anatomical locations not covered by more specific ill-defined site codes (head/neck, thorax, abdomen, pelvis, limbs). This is a catch-all code for overlapping or contiguous malignancies where the point of origin cannot be determined and no more specific ill-defined site code applies.
Documentation Requirements
- ✓Documentation confirming malignancy in a site not covered by C76.0-C76.52
- ✓Description of the anatomical location of the tumor
- ✓Pathology report with histological type
- ✓Thorough workup attempting to identify specific organ of origin
- ✓Justification for why a more specific code cannot be assigned