C65.9
BillableMalignant neoplasm of unspecified renal pelvis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C65.9 an HCC code?
Yes. C65.9 maps to Bladder, Colorectal, and Other Cancers 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 C65.9
For C65.9to 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 C65.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C65.9 is the ICD-10-CM diagnosis code for malignant neoplasm of unspecified renal pelvis. Cancer of the renal pelvis when the side (left or right) is not specified or documented. C65.9 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of urinary tract (c64-c68).
Under the CMS-HCC V28 risk adjustment model, C65.9 maps to Bladder, Colorectal, and Other Cancers (HCC 22) with a community, non-dual, aged base RAF weight of 0.363. Under the older CMS-HCC V24 model, C65.9 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.307. 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.
Review imaging and pathology reports to determine which kidney is affected. Because C65.9 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 C65.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Review imaging and pathology reports to determine which kidney is affected
- •Query the provider if laterality cannot be determined from available documentation
Clinical Significance
Unspecified renal pelvis cancer should be used only when laterality cannot be determined from any available documentation. In practice, imaging studies (CT urogram, MRI) always specify the side, making this code rarely appropriate. It carries audit risk and should prompt a query for laterality.
Documentation Requirements
- ✓Confirmation of renal pelvis malignancy
- ✓Evidence of query attempt for laterality
- ✓Imaging or pathology documentation
- ✓Treatment status