C50.522
BillableMalignant neoplasm of lower-outer quadrant of left male breast
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C50.522 an HCC code?
Yes. C50.522 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 C50.522
For C50.522 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 C50.522 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C50.522 is the ICD-10-CM diagnosis code for malignant neoplasm of lower-outer quadrant of left male breast. Cancer that develops in the lower-outer area of the left breast in men. C50.522 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, C50.522 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, C50.522 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.
Verify the patient is male and the cancer is located in the left breast lower-outer quadrant. Because C50.522 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 C50.522 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the patient is male and the cancer is located in the left breast lower-outer quadrant
- •Distinguish male breast cancer codes from female codes by checking the 4th digit (2 for male, 1 for female)
Clinical Significance
Male breast cancer of the lower-outer quadrant of the left breast represents a rare but clinically important diagnosis. Male breast cancer tends to present at a more advanced stage than female breast cancer due to lower awareness and delayed diagnosis. Accurate coding supports cancer surveillance programs and risk adjustment.
Documentation Requirements
- ✓Confirmed male patient sex
- ✓Laterality documented as left breast
- ✓Specific quadrant confirmed as lower-outer
- ✓Histological type and grade
- ✓TNM staging
- ✓Hormone receptor status (estrogen receptor, progesterone receptor)
- ✓Current treatment plan or surveillance status