D04.21 ICD-10-CM Code: Carcinoma in situ of skin of right ear and external auricular canal
D04.21 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Neoplasms (C00-D49) / In situ neoplasms (D00-D09)
D04.21
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCarcinoma in situ of skin of right ear and external auricular canal
This code describes an early-stage skin cancer on the right ear or ear canal that has not yet spread to deeper tissues or other parts of the body. It represents abnormal cells that have the potential to become invasive cancer if not treated.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for D04.21. Check the code and parent instructions in the Code Book.
Excludes 2
OfficialNo Excludes 2 notes are included in this display for D04.21. Check the code and parent instructions in the Code Book.
Related Codes
Includes
Official- Bowen's diseaseInherited from D00-D09
- erythroplasiaInherited from D00-D09
- grade III intraepithelial neoplasiaInherited from D00-D09
- Queyrat's erythroplasiaInherited from D00-D09
Excludes 1
Official- erythroplasia of Queyrat (penis) NOS (D07.4)Inherited from D04
- melanoma in situ (D03.-)Inherited from D04
Code First
OfficialNo Code First sequencing instructions are included in this display for D04.21. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for D04.21. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for D04.21. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is D04.21 an HCC code?
No. D04.21 is a billable ICD-10-CM code with no mapping under the CMS-HCC V28 or V24 community payment models, and none under the ESRD, Part D RxHCC, or HHS-HCC models.
- Code
- D04.21
- Description
- Carcinoma in situ of skin of right ear and external auricular canal
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
D04.21 is the ICD-10-CM diagnosis code for carcinoma in situ of skin of right ear and external auricular canal. This code describes an early-stage skin cancer on the right ear or ear canal that has not yet spread to deeper tissues or other parts of the body. It represents abnormal cells that have the potential to become invasive cancer if not treated. D04.21 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering in situ neoplasms (d00-d09).
D04.21 is a billable ICD-10-CM code, but the current payload does not show a mapping under the CMS-HCC V28 or V24 community payment models, and none under the ESRD, Part D RxHCC, or HHS-HCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.
Ensure laterality is documented as right ear (D04.21) versus left ear (D04.20) or bilateral (D04.22) to select the correct code.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D04.21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.