What is ICD-10 code C76.51?

C76.51 is the ICD-10-CM diagnosis code for Malignant neoplasm of right lower limb. Cancer that has developed in the right leg, thigh, knee, or foot area. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C76.51 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C76.51 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. C76.51 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. C76.51 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 C76.51?

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 C76.51, V28 maps to Prostate, Breast, and Other Cancers and Tumors at RAF 0.186 while V24 mapped to Breast, Prostate, and Other Cancers and Tumors at RAF 0.150. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C76.51?

Ensure documentation clearly specifies 'right' side before assigning this code This includes malignancies of the right hip, thigh, knee, lower leg, ankle, and foot Because C76.51 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 C76.51: Malignant neoplasm of right

ICD-10-CM Code View

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Code lookupC76.51Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)

C76.51

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

Malignant neoplasm of right lower limb

Cancer that has developed in the right leg, thigh, knee, or foot area.

Buddy Insight

Malignant neoplasm of the right lower limb specifies cancer in the right thigh, leg, or foot where the tissue of origin is ill-defined.

CMS-HCC V28

Mapped

HCC 23

Prostate, Breast, and Other C...

RAF 0.186

CMS-HCC V24

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.150

ACA/HHS

Mapped

HCC 12

HHS-HCC 12

Varies by metal level

ESRD/PACE

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.045

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.124

Code Book Path

Official

C76Malignant neoplasm of other and ill-defined sites

C76.5Malignant neoplasm of lower limb

C76.51Malignant neoplasm of right lower limb

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C76.51 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C76.51 in this effective period.

Related Child Codes

Official

C76.50Malignant neoplasm of unspecified lower limb

C76.52Malignant neoplasm of left lower limb

Includes

Official

ICD-10-CM does not list Includes notes for C76.51 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C76.51 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C76.51 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C76.51 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C76.51 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation confirming right lower limb malignancy

Pathology identifying tissue type for more specific coding

Imaging documenting location (thigh, leg, foot) and tumor extent

Neurovascular and functional assessment of the right lower extremity

MEAT Support

HCC Buddy guidance

Documentation confirming right lower limb malignancy

Pathology identifying tissue type for more specific coding

Imaging documenting location (thigh, leg, foot) and tumor extent

Neurovascular and functional assessment of the right lower extremity

Audit Caution

HCC Buddy guidance

Using ill-defined site code when bone, soft tissue, or skin origin is documented in pathology

Transposing laterality between right and left

Coding satellite metastases from melanoma in the right leg as a new primary

Not reviewing surgical pathology that identifies tissue of origin

Common Mistakes

HCC Buddy guidance

C76.52 — Left lower limb: Laterality error; confirm right side

C76.50 — Unspecified lower limb: Use C76.51 when right side is documented

C40.21 — Malignant neoplasm of long bones of right lower limb: Use for bone tumors

C49.21 — Connective tissue of right lower limb: Use for soft tissue sarcomas

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 C76.51 an HCC code?

Yes. C76.51 (Malignant neoplasm of right lower limb) maps to Prostate, Breast, and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors under V24), with a community non-dual aged RAF of 0.186. It is billable for payment year 2026.

Coder answer: C76.51 is billable and maps to V28 HCC 23, Prostate, Breast, and Other Cancers and Tumors. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C76.51
Description: Malignant neoplasm of right lower limb
HCC (V28): HCC 23 — Prostate, Breast, and Other Cancers and Tumors
RAF: 0.186
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 23, Prostate, Breast, and Other Cancers and Tumors

0.186

V24HCC 12, Breast, Prostate, and Other Cancers and Tumors

0.150

ESRDHCC 12, Breast, Prostate, and Other Cancers and Tumors

0.045

RxHCCHCC 22, Cancer, Other Specified Sites

0.124

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 C76.51 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C76.51

For C76.51 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 C76.51 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C76.51 is the ICD-10-CM diagnosis code for malignant neoplasm of right lower limb. Cancer that has developed in the right leg, thigh, knee, or foot area. C76.51 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).

Under the CMS-HCC V28 risk adjustment model, C76.51 maps to Prostate, Breast, and Other Cancers and Tumors (HCC 23) with a community, non-dual, aged base RAF weight of 0.186. Under the older CMS-HCC V24 model, C76.51 maps to Breast, Prostate, and Other Cancers and Tumors (HCC 12) with a community, non-dual, aged base RAF weight of 0.150. 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 documentation clearly specifies 'right' side before assigning this code. Because C76.51 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 C76.51 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Ensure documentation clearly specifies 'right' side before assigning this code
•This includes malignancies of the right hip, thigh, knee, lower leg, ankle, and foot

Clinical Significance

Malignant neoplasm of the right lower limb specifies cancer in the right thigh, leg, or foot where the tissue of origin is ill-defined. Lower extremity sarcomas (bone and soft tissue) are relatively more common in the lower limbs than upper limbs. Laterality documentation supports surgical planning and radiation targeting.

Documentation Requirements

✓Documentation confirming right lower limb malignancy
✓Pathology identifying tissue type for more specific coding
✓Imaging documenting location (thigh, leg, foot) and tumor extent
✓Neurovascular and functional assessment of the right lower extremity
✓Treatment plan including limb salvage vs. amputation considerations

Commonly Confused Codes

•C76.52: Left lower limb: Laterality error; confirm right side
•C76.50: Unspecified lower limb: Use C76.51 when right side is documented
•C40.21: Malignant neoplasm of long bones of right lower limb: Use for bone tumors
•C49.21: Connective tissue of right lower limb: Use for soft tissue sarcomas
•C43.71: Melanoma of right lower limb: Use for melanoma