C00.4
BillableMalignant neoplasm of lower lip, inner aspect
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C00.4 an HCC code?
No. C00.4 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
C00.4 is the ICD-10-CM diagnosis code for malignant neoplasm of lower lip, inner aspect. Cancer that starts on the inner surface (mucosa) of the lower lip. C00.4 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lip, oral cavity and pharynx (c00-c14).
C00.4 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify the location is the inner mucosal surface, not the external lip surface.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C00.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the location is the inner mucosal surface, not the external lip surface
- •Inner lip cancers may have different treatment approaches than external lip cancers