What is ICD-10 code C65.9?

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. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C65.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C65.9 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C65.9 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C65.9 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for C65.9?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C65.9, V28 maps to Bladder, Colorectal, and Other Cancers at RAF 0.363 while V24 mapped to Colorectal, Bladder, and Other Cancers at RAF 0.307. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C65.9?

Review imaging and pathology reports to determine which kidney is affected Query the provider if laterality cannot be determined from available documentation Because C65.9 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM C65.9: Malignant neoplasm

ICD-10-CM Code View

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Code lookupC65.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of urinary tract (C64-C68)

C65.9

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant neoplasm of unspecified renal pelvis

Cancer of the renal pelvis when the side (left or right) is not specified or documented.

Buddy Insight

Unspecified renal pelvis cancer should be used only when laterality cannot be determined from any available documentation.

CMS-HCC V28

Mapped

HCC 22

Bladder, Colorectal, and Othe...

RAF 0.363

CMS-HCC V24

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.307

ACA/HHS

Mapped

HCC 11

HHS-HCC 11

Varies by metal level

ESRD/PACE

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.059

RXHCC

Mapped

HCC 20

Cancer, Liver and Intrahepati...

RAF 0.491

Code Book Path

Official

C65Malignant neoplasm of renal pelvis

C65.9Malignant neoplasm of unspecified renal pelvis

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C65.9 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C65.9 in this effective period.

Related Child Codes

Official

C65.1Malignant neoplasm of right renal pelvis

C65.2Malignant neoplasm of left renal pelvis

Includes

Official

malignant neoplasm of pelviureteric junction
malignant neoplasm of renal calyces

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C65.9 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C65.9 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C65.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C65.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Confirmation of renal pelvis malignancy

Evidence of query attempt for laterality

Imaging or pathology documentation

Treatment status

MEAT Support

HCC Buddy guidance

Confirmation of renal pelvis malignancy

Evidence of query attempt for laterality

Imaging or pathology documentation

Treatment status

Audit Caution

HCC Buddy guidance

Not reviewing imaging studies that specify laterality

Confusing renal pelvis with kidney parenchyma

Using this code when bilateral renal pelvis cancers should be coded separately for each side

Common Mistakes

HCC Buddy guidance

C65.1/C65.2 — Laterality-specific renal pelvis cancer; always preferred

C64.9 — Unspecified kidney cancer; different anatomical structure

C68.9 — Unspecified urinary organ; renal pelvis is more specific

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C65.9 an HCC code?

Yes. C65.9 (Malignant neoplasm of unspecified renal pelvis) maps to Bladder, Colorectal, and Other Cancers under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, and Other Cancers under V24), with a community non-dual aged RAF of 0.363. It is billable for payment year 2026.

Coder answer: C65.9 is billable and maps to V28 HCC 22, Bladder, Colorectal, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C65.9
Description: Malignant neoplasm of unspecified renal pelvis
HCC (V28): HCC 22 — Bladder, Colorectal, and Other Cancers
RAF: 0.363
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 22, Bladder, Colorectal, and Other Cancers

0.363

V24HCC 11, Colorectal, Bladder, and Other Cancers

0.307

ESRDHCC 11, Colorectal, Bladder, and Other Cancers

0.059

RxHCCHCC 20, Cancer, Liver and Intrahepatic Bile Duct

0.491

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work C65.9 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C65.9

For C65.9 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 C65.9 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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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.