C50.A1 ICD-10-CM Code: Malignant inflammatory neoplasm of right breast
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of breast (C50)
C50.A1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMalignant inflammatory neoplasm of right breast
Inflammatory breast cancer affecting the right breast. This is an aggressive form of cancer characterized by inflammation, redness, and swelling of the right breast tissue.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
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
Official- Inflammatory breast cancer (IBC)
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C50.A1 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C50.A1 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for C50.A1 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C50.A1 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C50.A1 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C50.A1 in this effective period.
Buddy Documentation Tip
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.A1 an HCC code?
No. C50.A1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
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.
Work C50.A1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for C50.A1
For C50.A1to 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.A1 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
Get the V28 RAF + MEAT cheat sheet
One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.
Free PDF. No card. Unsubscribe anytime.
What This Code Means
C50.A1 is the ICD-10-CM diagnosis code for malignant inflammatory neoplasm of right breast. Inflammatory breast cancer affecting the right breast. This is an aggressive form of cancer characterized by inflammation, redness, and swelling of the right breast tissue. C50.A1 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of breast (c50).
C50.A1 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Ensure documentation explicitly identifies this as inflammatory breast cancer, not just general breast cancer with inflammation.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C50.A1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure documentation explicitly identifies this as inflammatory breast cancer, not just general breast cancer with inflammation
- •Confirm laterality is documented as right; use C50.A0 if laterality is unspecified