C50.811
BillableMalignant neoplasm of overlapping sites of right female breast
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C50.811 an HCC code?
Yes. C50.811 maps to Melanoma and Other Skin Cancers under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors 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 C50.811
For C50.811 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 C50.811 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C50.811 is the ICD-10-CM diagnosis code for malignant neoplasm of overlapping sites of right female breast. Cancer that involves multiple overlapping areas of the right female breast rather than being confined to a single quadrant or region. C50.811 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of breast (c50).
Under the CMS-HCC V28 risk adjustment model, C50.811 maps to Melanoma and Other Skin Cancers (HCC 23) with a community, non-dual, aged base RAF weight of 0.251. Under the older CMS-HCC V24 model, C50.811 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.
Use this code when the tumor spans two or more distinct anatomical regions of the breast. Because C50.811 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 C50.811 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code when the tumor spans two or more distinct anatomical regions of the breast
- •Overlapping site designation may indicate more advanced local disease; ensure documentation supports this classification
Clinical Significance
Overlapping sites of the right female breast indicates a malignancy that spans multiple anatomical regions of the breast, which typically suggests a larger or more advanced tumor. This code is specifically designated for tumors that cannot be classified to a single breast subsite, carrying implications for staging, treatment planning, and prognosis.
Documentation Requirements
- ✓Confirmed female patient sex
- ✓Laterality documented as right breast
- ✓Documentation that the tumor involves two or more distinct anatomical subsites
- ✓Specific subsites involved identified in pathology or imaging
- ✓Tumor size and extent of local invasion
- ✓TNM staging and lymph node status
- ✓Histological type and receptor status
Commonly Confused Codes
- •C50.911 — Unspecified site of right female breast; used when the exact site is unknown, not when multiple known sites are involved
- •C50.411 — Upper-outer quadrant of right female breast; use when the primary site is confined to one quadrant
- •C50.812 — Overlapping sites of left female breast; laterality error
- •C80.1 — Malignant neoplasm without specification of site; this is far too nonspecific when the breast is identified