C57.3
BillableMalignant neoplasm of parametrium
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C57.3 an HCC code?
Yes. C57.3 maps to Colorectal, Bladder, and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma 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 C57.3
For C57.3 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 C57.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C57.3 is the ICD-10-CM diagnosis code for malignant neoplasm of parametrium. Cancer that develops in the parametrium, the connective tissue surrounding the uterus that provides structural support. C57.3 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, C57.3 maps to Colorectal, Bladder, and Other Cancers (HCC 22) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, C57.3 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. 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.
Parametrial cancers are often secondary to uterine cancer; verify if this is primary or extension. Because C57.3 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 C57.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Parametrial cancers are often secondary to uterine cancer; verify if this is primary or extension
- •Document whether cancer is confined to parametrium or extends to adjacent structures
Clinical Significance
Parametrial cancer involves the connective tissue surrounding the lower portion of the uterus between the layers of the broad ligament. Primary parametrial malignancies are rare; most parametrial involvement represents direct extension of cervical cancer (FIGO Stage IIB or higher). Distinguishing primary from secondary parametrial cancer is critical for accurate coding and staging.
Documentation Requirements
- ✓Pathology or imaging confirming parametrial malignancy
- ✓Whether the parametrial cancer is primary or secondary to cervical/uterine extension
- ✓FIGO or TNM staging
- ✓Histologic type and grade
- ✓Extent of parametrial involvement (unilateral vs. bilateral, extent to pelvic wall)
- ✓Active treatment versus surveillance status