C79.63
BillableSecondary malignant neoplasm of bilateral ovaries
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C79.63 an HCC code?
Yes. C79.63 maps to Metastatic Cancer to Peritoneum and Other Specified Sites under the CMS-HCC V28 risk adjustment model (and Metastatic Cancer and Acute Leukemia 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 C79.63
For C79.63 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 C79.63 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C79.63 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of bilateral ovaries. Cancer that has spread to both ovaries from a primary cancer site elsewhere in the body. C79.63 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, C79.63 maps to Metastatic Cancer to Peritoneum and Other Specified Sites (HCC 18) with a community, non-dual, aged base RAF weight of 0.368. Under the older CMS-HCC V24 model, C79.63 maps to Metastatic Cancer and Acute Leukemia (HCC 8) with a community, non-dual, aged base RAF weight of 2.484. 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.
This code indicates bilateral involvement; ensure documentation confirms cancer in both ovaries. Because C79.63 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 C79.63 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Secondary malignant neoplasm of bilateral ovaries indicates metastatic cancer involving both ovaries. Bilateral ovarian metastases are characteristic of Krukenberg tumors from gastrointestinal primaries and may also occur with breast or uterine cancer. Bilateral involvement typically indicates more extensive peritoneal spread and carries a poorer prognosis than unilateral disease.
Documentation Requirements
- ✓Primary cancer site documented and coded separately
- ✓Explicit documentation confirming cancer in BOTH ovaries
- ✓Pathological confirmation of metastatic origin in both ovaries
- ✓Imaging showing bilateral ovarian masses
- ✓Assessment for associated peritoneal carcinomatosis — code C78.6 if present
- ✓Bilateral salpingo-oophorectomy status if performed