2026 ICD-10-CM Diagnosis Code C05.0Malignant neoplasm of hard palate

ICD-10-CM Codes›C00–D49›C00-C14›C05

ICD-10-CM C05.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C05.0 is a billable ICD-10-CM diagnosis code for malignant neoplasm of hard 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 hard 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, C05.0 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

ICD-10-CM Code
C05.0
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of hard palate
Short Description
Malignant neoplasm of hard palate
Same as the full description in the CMS dataset.
Parent Code
C05
Malignant neoplasm of palate

Code Classification

ChapterC00–D49Neoplasms
SectionC00-C14Malignant neoplasms of lip, oral cavity and pharynx
CategoryC05Malignant neoplasm of palate
This CodeC05.0Malignant neoplasm of hard palate

Medicare Risk Adjustment (HCC)Billing

C05.0 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.

CMS-HCC V28 Category (Payment Model)
HCC 21— Lymphoma and Other Cancers
Payment HCC · PY 2026 one of 463 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.671
community, non-dual, aged · ranges 0.493–0.739 across segments
Hierarchy
Superseded by HCC 17, HCC 18, HCC 19, and HCC 20
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 11
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 11 · ESRD (V21): HCC 11 · ESRD (V24): HCC 11
ESRD V21 weights: 0.076 dialysis, 0.284–0.298 functioning graft · ESRD V24 weights: 0.059 dialysis, 0.257–0.362 functioning graft
Part D (RxHCC)
RxHCC 22 — Prostate, Breast, Bladder, and Other Cancers and Tumors
also risk-adjusts in the Part D prescription drug model (V08)

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 hard palate
  • Malignant neoplasm of hard palate
  • Palate carcinoma
  • Primary carcinoma of hard palate
  • Primary malignant neoplasm of hard palate
  • Primary palate carcinoma
  • Primary squamous cell carcinoma of hard palate

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO002
Head and neck cancers - lip and oral cavity
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
palate › hardC05.0C79.89D00.05D10.39D37.09D49.0

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 C05.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
145.2 Malig neo hard palate
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C05.0Overview

What is the ICD-10 code for malignant neoplasm of hard palate?

The ICD-10-CM code for malignant neoplasm of hard palate is C05.0 (sometimes written as C050). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is C05.0 (Malignant neoplasm of palate) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of hard palate on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C05.0 group to?

When malignant neoplasm of hard 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 C05.0?

Under the General Equivalence Mappings, malignant neoplasm of hard palate converts to ICD-9-CM 145.2 (malig neo hard palate). The mapping is a direct match.

What HCC is C05.0?

C05.0 (malignant neoplasm of hard 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 C05.0 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, C05.0 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.