C57.9
BillableMalignant neoplasm of female genital organ, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C57.9 an HCC code?
Yes. C57.9 maps to Colorectal, Bladder, 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 C57.9
For C57.9 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 C57.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C57.9 is the ICD-10-CM diagnosis code for malignant neoplasm of female genital organ, unspecified. Cancer of a female genital organ when the specific organ or structure involved cannot be determined or identified. C57.9 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of female genital organs (c51-c58).
Under the CMS-HCC V28 risk adjustment model, C57.9 maps to Colorectal, Bladder, and Other Cancers (HCC 22) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, C57.9 mapped to the same category but with a base RAF weight of 0.306 — V28 recalibrated weights across the entire model. 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 is the least specific code in the C57 category; attempt to obtain more specific site information. Because C57.9 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 C57.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is the least specific code in the C57 category; attempt to obtain more specific site information
- •Request clarification from the provider if the cancer location is not documented
Clinical Significance
This is the least specific code for female genital organ malignancy, used only when the provider documents cancer of a female genital organ but does not specify which organ is affected. In risk adjustment, this code raises red flags for insufficient documentation and is a prime target for coding audits. Provider queries should always be pursued before defaulting to this code.
Documentation Requirements
- ✓Documentation of a confirmed malignancy of a female genital organ
- ✓Evidence that provider query was attempted to identify the specific organ
- ✓Explanation of why the specific organ cannot be determined
- ✓Current treatment status and plan