2026 ICD-10-CM Diagnosis Code C00.6Malignant neoplasm of commissure of lip, unspecified

ICD-10-CM Codes›C00–D49›C00-C14›C00

ICD-10-CM C00.6
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C00.6 is a billable ICD-10-CM diagnosis code for malignant neoplasm of commissure of lip, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 146 through 148. Coders also document this condition as carcinoma of commissure of lip. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - lip and oral cavity.

Code Identity

ICD-10-CM Code
C00.6
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of commissure of lip, unspecified
Short Description
Malignant neoplasm of commissure of lip, unspecified
Same as the full description in the CMS dataset.
Parent Code
C00
Malignant neoplasm of lip

Code Classification

ChapterC00–D49Neoplasms
SectionC00-C14Malignant neoplasms of lip, oral cavity and pharynx
CategoryC00Malignant neoplasm of lip
This CodeC00.6Malignant neoplasm of commissure of lip, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Carcinoma of commissure of lip
  • Malignant neoplasm of commissure of lips
  • Neoplasm of commissure of lip
  • Primary carcinoma of commissure of lip
  • Primary carcinoma of lip
  • Primary malignant neoplasm of commissure of lip

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.
commissureC00.6C79.89D00.01D10.39D37.01D49.0
commissure › labial, lipC00.6C79.89D00.01D10.39D37.01D49.0
lip › commissureC00.6C79.89D00.01D10.0D37.01D49.0

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 C00.6 to ICD-9-CMHistory

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

ICD-9-CM
140.6 Mal neo lip, commissure
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 C00.6Overview

Is C00.6 (Malignant neoplasm of lip) a billable code?

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

What MS-DRG does C00.6 group to?

When malignant neoplasm of commissure of lip, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 146, 147, 148, with relative weights from 0.7971 to 2.1174 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C00.6?

Under the General Equivalence Mappings, malignant neoplasm of commissure of lip, unspecified converts to ICD-9-CM 140.6 (mal neo lip, commissure). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.