C11.3
BillableMalignant neoplasm of anterior wall of nasopharynx
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C11.3 an HCC code?
Yes. C11.3 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 C11.3
For C11.3 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 C11.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C11.3 is the ICD-10-CM diagnosis code for malignant neoplasm of anterior wall of nasopharynx. Cancer that forms in the front wall of the nasopharynx, the uppermost part of the throat. C11.3 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, C11.3 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, C11.3 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 anterior wall location is explicitly documented in the pathology or imaging report. Because C11.3 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 C11.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure the anterior wall location is explicitly documented in the pathology or imaging report
- •This location may be associated with different symptom presentations compared to posterior wall tumors
Clinical Significance
Malignant neoplasm of the anterior wall of the nasopharynx involves the surface facing the nasal cavity, including the choana (posterior nasal apertures). This location may cause nasal obstruction and epistaxis as early symptoms, and tumors may extend anteriorly into the nasal cavity, complicating primary site determination.
Documentation Requirements
- ✓Pathology-confirmed malignancy with histological type
- ✓Documentation specifying anterior wall of nasopharynx
- ✓EBV status
- ✓Assessment of nasal cavity extension through choana
- ✓MRI staging including evaluation of both nasal and nasopharyngeal extent