2026 ICD-10-CM Diagnosis Code C05.1Malignant neoplasm of soft palate
ICD-10-CM Codes›C00–D49›C00-C14›C05
- Billable — Valid for Submission
- Risk Adjusts — HCC 21
- Chronic Condition
C05.1 is a billable ICD-10-CM diagnosis code for malignant neoplasm of soft palate. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 146 through 148. Coders also document this condition as carcinoma of soft palate. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - lip and oral cavity.
For Medicare Advantage risk adjustment, C05.1 maps to CMS-HCC Category 21 (Lymphoma and Other Cancers) under the V28 model, adding a risk factor of about 0.671 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C05.1 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Carcinoma of soft palate
- Malignant neoplasm of inferior surface of soft palate
- Malignant neoplasm of soft palate
- Neoplasm of inferior surface of soft palate
- Palate carcinoma
- Primary carcinoma of soft palate
- Primary malignant neoplasm of soft palate
- Primary palate carcinoma
- Primary squamous cell carcinoma of soft palate
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 2 Excludes
- malignant neoplasm of nasopharyngeal surface of soft palate C11.3
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Patient EducationClinical
Oral Cancer
Oral cancer is cancer of the mouth. It is a type of head and neck cancer. Most oral cancers are squamous cell cancers. They begin in the flat cells that cover the surfaces of your mouth, tongue, and lips. The cancer cells may spread into deeper tissue as the cancer grows.
The full article covers:
- What is oral cancer?
- Who is more likely to develop oral cancer?
- What are the symptoms of oral cancer?
- How is oral cancer diagnosed?
- What are the treatments for oral cancer?
- Can oral cancer be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C05.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C05.1Overview
What is the ICD-10 code for malignant neoplasm of soft palate?
The ICD-10-CM code for malignant neoplasm of soft palate is C05.1 (sometimes written as C051). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is C05.1 (Malignant neoplasm of palate) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of soft palate on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C05.1 group to?
When malignant neoplasm of soft palate is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 146, 147, 148, with relative weights from 0.7971 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C05.1?
Under the General Equivalence Mappings, malignant neoplasm of soft palate converts to ICD-9-CM 145.3 (malig neo soft palate). The mapping is a direct match.
What HCC is C05.1?
C05.1 (malignant neoplasm of soft palate) maps to CMS-HCC Category 21 (Lymphoma and Other Cancers), commonly written as HCC 21, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 11 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.
Does C05.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C05.1 adds a risk adjustment factor of about 0.671 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.493 to 0.739 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, and HCC 20) supersedes it when both are reported. See the full factor table on the HCC 21 category page.
