C50.821
BillableMalignant neoplasm of overlapping sites of right male breast
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C50.821 an HCC code?
Yes. C50.821 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 C50.821
For C50.821 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 C50.821 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C50.821 is the ICD-10-CM diagnosis code for malignant neoplasm of overlapping sites of right male breast. Cancer that involves multiple areas of the right breast in a male patient. This occurs when the tumor spans across different regions of the breast tissue. C50.821 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, C50.821 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, C50.821 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 documentation indicates cancer affecting more than one specific site in the right male breast. Because C50.821 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 C50.821 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code when documentation indicates cancer affecting more than one specific site in the right male breast
- •Ensure laterality is clearly documented as right; if unspecified, use C50.829 instead
Clinical Significance
Overlapping sites of the right male breast indicates a malignancy that spans multiple breast regions in a male patient. Given the smaller amount of breast tissue in males, overlapping site designation may suggest locally advanced disease at the time of diagnosis, which is consistent with the typically later presentation of male breast cancer.
Documentation Requirements
- ✓Confirmed male patient sex
- ✓Laterality documented as right breast
- ✓Documentation that the tumor involves two or more breast subsites
- ✓Histological type and grade
- ✓TNM staging and extent of local invasion
- ✓Receptor status and treatment plan
- ✓Assessment of chest wall involvement if applicable