C30.1
BillableMalignant neoplasm of middle ear
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C30.1 an HCC code?
Yes. C30.1 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 C30.1
For C30.1 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 C30.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C30.1 is the ICD-10-CM diagnosis code for malignant neoplasm of middle ear. Cancer of the middle ear, the air-filled space behind the eardrum that contains tiny bones for hearing. C30.1 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of respiratory and intrathoracic organs (c30-c39).
Under the CMS-HCC V28 risk adjustment model, C30.1 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, C30.1 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.
Middle ear cancer is rare; verify diagnosis carefully and ensure it is not metastatic disease from another site. Because C30.1 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 C30.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Middle ear cancer is rare; verify diagnosis carefully and ensure it is not metastatic disease from another site
- •Document whether the cancer involves the mastoid bone or extends beyond the middle ear
Clinical Significance
Middle ear cancer is extremely rare, and most middle ear malignancies are squamous cell carcinomas often associated with chronic otitis media. Due to its rarity, this diagnosis requires careful verification to ensure it is not metastatic disease from another site. These tumors are aggressive and frequently involve the temporal bone, requiring complex surgical management.
Documentation Requirements
- ✓Pathology confirmation of primary middle ear malignancy
- ✓Imaging (CT/MRI temporal bone) documenting tumor extent
- ✓Verification that the tumor is primary to the middle ear, not metastatic
- ✓Documentation of any extension into mastoid, inner ear, or intracranial structures
- ✓Treatment plan and stage