C50.212 ICD-10-CM Code: Malignant neoplasm of upper-inner quadrant of left female breast
HCC Buddy Code Card
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of breast (C50)
C50.212
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMalignant neoplasm of upper-inner quadrant of left female breast
Cancer that develops in the upper-inner quadrant (upper inner section) of the left female breast.
Buddy Insight
Malignant neoplasm of the upper-inner quadrant of left female breast represents invasive breast cancer requiring staging, treatment planning, and ongoing surveillance.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 12
RAF 0.150
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 12
RAF 0.0
RXHCC
MappedHCC 22
RAF 0.0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for C50.212 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C50.212 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C50.212 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for C50.212 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C50.212 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C50.212 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C50.212 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is C50.212 an HCC code?
Yes. C50.212 maps to Breast, Prostate, and Other Cancers and Tumors under the V24 model but is not retained in V28.
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 C50.212
For C50.212to 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 C50.212 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
C50.212 is the ICD-10-CM diagnosis code for malignant neoplasm of upper-inner quadrant of left female breast. Cancer that develops in the upper-inner quadrant (upper inner section) of the left female breast. C50.212 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of breast (c50).
Under the older CMS-HCC V24 model, C50.212 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.
The upper-inner quadrant is located toward the armpit and upper chest area; confirm anatomical location in documentation. Because C50.212 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 C50.212 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The upper-inner quadrant is located toward the armpit and upper chest area; confirm anatomical location in documentation
- •Verify laterality is documented as left; if right or unspecified, different codes apply
Clinical Significance
Malignant neoplasm of the upper-inner quadrant of left female breast represents invasive breast cancer requiring staging, treatment planning, and ongoing surveillance. Breast cancer is risk-adjusted because it demands significant healthcare resources including surgery, radiation, chemotherapy, hormonal therapy, and long-term monitoring.
Documentation Requirements
- ✓Pathologic confirmation of invasive malignancy (biopsy with histologic type — ductal, lobular, etc.)
- ✓Laterality: left breast
- ✓Gender documented as female to support gender-specific code selection
- ✓Quadrant or subsite location: upper-inner quadrant
- ✓Tumor size (T stage) and grade
- ✓Lymph node status (N stage) — axillary, sentinel node biopsy results
- ✓Estrogen receptor, progesterone receptor, and HER2 status
- ✓Stage grouping (I-IV)
- ✓Current treatment status (active treatment, hormonal therapy, surveillance)
Commonly Confused Codes
- •C50.211 — Upper-inner quadrant of right female breast; verify laterality
- •C50.219 — Upper-inner quadrant unspecified female; use only when laterality unknown
- •C50.222 — Same laterality but male breast; verify patient gender
- •C50.411-C50.419 — Upper-outer quadrant; upper-inner is toward the sternum, upper-outer is toward the axilla — most common confusion
- •C50.111-C50.119 — Central portion; adjacent to upper-inner but anatomically distinct
- •C50.311-C50.319 — Lower-inner quadrant; same medial orientation but lower position