C06.0
BillableMalignant neoplasm of cheek mucosa
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C06.0 an HCC code?
Yes. C06.0 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, and Other 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 C06.0
For C06.0to 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 C06.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C06.0 is the ICD-10-CM diagnosis code for malignant neoplasm of cheek mucosa. Cancer that develops in the mucosa (lining tissue) of the cheek, the soft tissue inside the side of the mouth. C06.0 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).
Under the CMS-HCC V28 risk adjustment model, C06.0 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C06.0 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.306. 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.
Cheek mucosa cancers may involve buccal mucosa; document location precisely. Because C06.0 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 C06.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Cheek mucosa cancers may involve buccal mucosa; document location precisely
- •Note involvement of underlying muscle or bone if present
Clinical Significance
Malignant neoplasm of the cheek mucosa (buccal mucosa) is an oral cavity cancer with particular clinical significance due to its association with smokeless tobacco and betel nut use. These cancers can be locally aggressive with potential for deep invasion into the buccinator muscle and cheek fat pad.
Documentation Requirements
- ✓Biopsy-confirmed malignancy with histological type
- ✓Specific documentation of cheek mucosa or buccal mucosa as primary site
- ✓Depth of invasion into underlying muscle or fat pad
- ✓Laterality (right or left cheek)
- ✓TNM staging including nodal status and tobacco/betel nut exposure history
Commonly Confused Codes
- •C06.1 — Vestibule of mouth; the vestibule is the space between the cheek and teeth/gums, while cheek mucosa lines the inner cheek surface
- •C06.2 — Retromolar area; posterior cheek tumors may be confused with retromolar cancers
- •C44.309 — Skin of cheek; distinguish internal cheek mucosa cancer from external skin cancer of the cheek
- •C06.9 — Mouth, unspecified; avoid when cheek mucosa is documented