What is ICD-10 code C79.61?

C79.61 is the ICD-10-CM diagnosis code for Secondary malignant neoplasm of right ovary. Cancer that has spread to the right ovary from a cancer that started elsewhere in the body. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C79.61 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C79.61 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. C79.61 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. C79.61 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 C79.61?

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 C79.61, V28 maps to Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid at RAF 2.341 while V24 mapped to Metastatic Cancer and Acute Leukemia at RAF 2.659. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C79.61?

Ensure documentation clearly specifies 'right ovary' to differentiate from left or bilateral involvement. Always sequence the primary malignancy code before this secondary cancer code. Because C79.61 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 C79.61: Secondary malignant neoplasm

ICD-10-CM Code View

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Code lookupC79.61Effective 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)

C79.61

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

Secondary malignant neoplasm of right ovary

Cancer that has spread to the right ovary from a cancer that started elsewhere in the body.

Buddy Insight

Secondary malignant neoplasm of the right ovary with documented laterality confirms metastatic disease from a primary cancer elsewhere.

CMS-HCC V28

Mapped

HCC 18

Cancer Metastatic to Bone, Ot...

RAF 2.341

CMS-HCC V24

Mapped

HCC 8

Metastatic Cancer and Acute L...

RAF 2.659

ACA/HHS

Mapped

HCC 8

HHS-HCC 8

Varies by metal level

ESRD/PACE

Mapped

HCC 8

Metastatic Cancer and Acute L...

RAF 0.353

RXHCC

Mapped

HCC 18

Metastatic Cancer to Lung and...

RAF 1.949

Code Book Path

Official

C79Secondary malignant neoplasm of other and unspecified sites

C79.6Secondary malignant neoplasm of ovary

C79.61Secondary malignant neoplasm of right ovary

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C79.61 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C79.61 in this effective period.

Related Child Codes

Official

C79.60Secondary malignant neoplasm of unspecified ovary

C79.62Secondary malignant neoplasm of left ovary

C79.63Secondary malignant neoplasm of bilateral ovaries

Includes

Official

ICD-10-CM does not list Includes notes for C79.61 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C79.61 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C79.61 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C79.61 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C79.61 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Primary cancer site documented and coded separately

Explicit documentation of right ovary involvement — operative report, imaging, or pathology

Pathological confirmation of metastatic histology consistent with the known primary site

Imaging showing right ovarian mass or enlargement

MEAT Support

HCC Buddy guidance

Primary cancer site documented and coded separately

Explicit documentation of right ovary involvement — operative report, imaging, or pathology

Pathological confirmation of metastatic histology consistent with the known primary site

Imaging showing right ovarian mass or enlargement

Audit Caution

HCC Buddy guidance

Using unspecified laterality when right ovary is clearly documented in operative or pathology reports

Assuming all ovarian masses are primary ovarian cancer without pathological confirmation

Not coding bilateral involvement (C79.63) when both ovaries are affected

Failing to code the primary cancer site that metastasized to the right ovary

Common Mistakes

HCC Buddy guidance

C56.1 — Primary malignant neoplasm of right ovary; distinguish primary from metastatic ovarian cancer

C79.60 — Secondary malignant neoplasm of unspecified ovary; use C79.61 when right side is documented

C79.62 — Secondary malignant neoplasm of left ovary; verify laterality

C79.63 — Secondary malignant neoplasm of bilateral ovaries; if both ovaries are involved, use bilateral code

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C79.61 an HCC code?

Yes. C79.61 (Secondary malignant neoplasm of right ovary) maps to Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid under the CMS-HCC V28 risk adjustment model (and Metastatic Cancer and Acute Leukemia under V24), with a community non-dual aged RAF of 2.341. It is billable for payment year 2026.

Coder answer: C79.61 is billable and maps to V28 HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C79.61
Description: Secondary malignant neoplasm of right ovary
HCC (V28): HCC 18 — Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid
RAF: 2.341
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid

2.341

V24HCC 8, Metastatic Cancer and Acute Leukemia

2.659

ESRDHCC 8, Metastatic Cancer and Acute Leukemia

0.353

RxHCCHCC 18, Metastatic Cancer to Lung and Other Respiratory Sites

1.949

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 C79.61 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C79.61

For C79.61to 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 C79.61 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C79.61 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of right ovary. Cancer that has spread to the right ovary from a cancer that started elsewhere in the body. C79.61 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, C79.61 maps to Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid (HCC 18) with a community, non-dual, aged base RAF weight of 2.341. Under the older CMS-HCC V24 model, C79.61 maps to Metastatic Cancer and Acute Leukemia (HCC 8) with a community, non-dual, aged base RAF weight of 2.659. 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 ovary' to differentiate from left or bilateral involvement. Because C79.61 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 C79.61 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 ovary' to differentiate from left or bilateral involvement.
•Always sequence the primary malignancy code before this secondary cancer code.

Clinical Significance

Secondary malignant neoplasm of the right ovary with documented laterality confirms metastatic disease from a primary cancer elsewhere. Right ovarian metastases most commonly originate from gastrointestinal primaries (Krukenberg tumor), breast cancer, or uterine cancer. Specific laterality documentation supports surgical planning and monitoring.

Documentation Requirements

✓Primary cancer site documented and coded separately
✓Explicit documentation of right ovary involvement — operative report, imaging, or pathology
✓Pathological confirmation of metastatic histology consistent with the known primary site
✓Imaging showing right ovarian mass or enlargement
✓Tumor marker profile to help distinguish metastatic from primary ovarian cancer

Commonly Confused Codes

•C56.1: Primary malignant neoplasm of right ovary; distinguish primary from metastatic ovarian cancer
•C79.60: Secondary malignant neoplasm of unspecified ovary; use C79.61 when right side is documented
•C79.62: Secondary malignant neoplasm of left ovary; verify laterality
•C79.63: Secondary malignant neoplasm of bilateral ovaries; if both ovaries are involved, use bilateral code