C06.2
BillableMalignant neoplasm of retromolar area
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C06.2 an HCC code?
Yes. C06.2 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 C06.2
For C06.2 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 C06.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C06.2 is the ICD-10-CM diagnosis code for malignant neoplasm of retromolar area. Cancer that develops in the retromolar area, which is the tissue behind the last upper molar tooth. C06.2 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, C06.2 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, C06.2 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.
Ensure the retromolar location is clearly documented to differentiate from other oral sites. Because C06.2 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 C06.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure the retromolar location is clearly documented to differentiate from other oral sites
- •Document any extension to adjacent structures for potential higher specificity codes
Clinical Significance
Malignant neoplasm of the retromolar area involves cancer in the mucosal tissue behind the last molar tooth. This is a clinically important site because retromolar cancers frequently invade the mandible and may extend into the tonsillar region or pterygoid musculature, often presenting at an advanced stage.
Documentation Requirements
- ✓Pathology-confirmed malignancy with biopsy from retromolar area
- ✓Specific documentation of retromolar trigone or retromolar area as primary site
- ✓Assessment of mandibular bone invasion on imaging (CT or MRI)
- ✓Evaluation of extension to pterygomandibular raphe, tonsillar region, or buccal mucosa
- ✓TNM staging with nodal assessment
Commonly Confused Codes
- •C03.1 — Malignant neoplasm of lower gum; the retromolar area is behind the last molar, while gum cancer involves the gingiva along the teeth
- •C09.0 — Tonsillar fossa; retromolar tumors may extend posteriorly to the tonsillar region
- •C06.0 — Cheek mucosa; retromolar tumors may extend laterally into the buccal mucosa
- •C06.89 — Overlapping sites of mouth; use when tumor extends significantly beyond the retromolar area