C10.9
BillableMalignant neoplasm of oropharynx, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C10.9 an HCC code?
Yes. C10.9 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 C10.9
For C10.9 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 C10.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C10.9 is the ICD-10-CM diagnosis code for malignant neoplasm of oropharynx, unspecified. Cancer of the oropharynx where the specific location within the middle throat is not documented or specified in the medical record. C10.9 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, C10.9 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, C10.9 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.
This is a default code used when oropharyngeal cancer is diagnosed but the exact anatomical site is not specified. Because C10.9 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 C10.9 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 oropharynx, unspecified, is the least specific oropharyngeal cancer code and should be used only when the precise subsite truly cannot be determined from available documentation. Given the prognostic and treatment importance of exact oropharyngeal site identification, this code signals a documentation improvement opportunity.
Documentation Requirements
- ✓Pathology confirmation of oropharyngeal malignancy
- ✓Documentation of provider query for specific subsite
- ✓HPV/p16 status (critical for all oropharyngeal cancers)
- ✓Review of all imaging and endoscopy reports for subsite identification
- ✓Explanation for why specific subsite cannot be determined
Commonly Confused Codes
- •C10.0 — Vallecula; check endoscopy reports for specific subsite
- •C09.9 — Tonsil, unspecified; more specific if at least tonsillar origin is known
- •C14.0 — Pharynx, unspecified; even less specific — use C10.9 when at least oropharynx is identified
- •C10.2 — Lateral wall of oropharynx; frequently identifiable on imaging