2026 ICD-10-CM Diagnosis Code K13.70Unspecified lesions of oral mucosa

ICD-10-CM Codes›K00–K95›K00-K14›K13

ICD-10-CM K13.70
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K13.70 is a billable ICD-10-CM diagnosis code for unspecified lesions of oral mucosa. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 157 through 159. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Diseases of mouth; excluding dental, and Nontraumatic dental conditions.

Code Identity

ICD-10-CM Code
K13.70
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified lesions of oral mucosa
Short Description
Unspecified lesions of oral mucosa
Same as the full description in the CMS dataset.
Parent Code
K13.7
Other and unspecified lesions of oral mucosa

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK13Other diseases of lip and oral mucosa
This CodeK13.70Unspecified lesions of oral mucosa

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disease of mouth
  • Disorder of oral mucous membrane
  • Drug-induced oral condition
  • Fixed drug reaction
  • Fixed drug reaction affecting oral mucous membranes
  • Impaired oral mucous membrane
  • Impaired tissue integrity
  • Infectious disease of oral mucosa
  • Iron pigmentation of oral mucosa
  • Lesion of oral mucosa
  • Oral cavity problem
  • Oral cavity, dental and salivary gland disorder
  • Oral lesion
  • Oral lesion co-occurrent with reactive arthritis triad
  • Pigmented oral mucosal lesion
  • Reactive arthritis of spine
  • Reactive arthritis triad
  • Skin and mucous membrane disorder of mouth, lips and tongue
  • Swelling of oral cavity structure

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Lesion(s) (nontraumatic)
      • oral mucosa

Clinical ClassificationClinical

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

CCSR DEN001
Any dental condition including traumatic injury
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG003
Diseases of mouth; excluding dental
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Mouth Disorders

Your mouth is one of the most important parts of your body. It has many different functions. It allows you to:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K13.70 to ICD-9-CMHistory

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

ICD-9-CM
528.9 Oral soft tissue dis NEC
Approximate The match is approximate rather than exact.

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 K13.70Overview

Is K13.70 (Other and unspecified lesions of oral mucosa) a billable code?

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

What MS-DRG does K13.70 group to?

When unspecified lesions of oral mucosa is the principal diagnosis on an inpatient stay, it groups to MS-DRG 157, 158, 159, with relative weights from 0.7085 to 1.7168 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K13.70?

Under the General Equivalence Mappings, unspecified lesions of oral mucosa converts to ICD-9-CM 528.9 (oral soft tissue dis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.