2026 ICD-10-CM Diagnosis Code L91.9Hypertrophic disorder of the skin, unspecified

ICD-10-CM Codes›L00–L99›L80-L99›L91

ICD-10-CM L91.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L91.9 is a billable ICD-10-CM diagnosis code for hypertrophic disorder of the skin, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607. Coders also document this condition as hypertrophic condition of skin. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified skin disorders.

Code Identity

ICD-10-CM Code
L91.9
Billable Status
Yes — Valid for Submission
Code Describes
Hypertrophic disorder of the skin, unspecified
Short Description
Hypertrophic disorder of the skin, unspecified
Same as the full description in the CMS dataset.
Parent Code
L91
Hypertrophic disorders of skin

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL80-L99Other disorders of the skin and subcutaneous tissue
CategoryL91Hypertrophic disorders of skin
This CodeL91.9Hypertrophic disorder of the skin, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hypertrophic condition of skin
  • Skin graft hypertrophy

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.

    • Disorder(of)
      • skin
        • hypertrophic
    • Hypertrophy, hypertrophic
      • skin

Clinical ClassificationClinical

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

CCSR SKN007
Other specified and unspecified skin disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Skin Conditions

Your skin is your body's largest organ. It covers the entire outside of your body. There are many ways that your skin protects your body and helps keep you healthy. For example, it:

The full article covers:

  • What does your skin do?
  • What problems and conditions can affect your skin?
  • How can I keep my skin healthy?

Read the full article at MedlinePlus

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

Convert L91.9 to ICD-9-CMHistory

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

ICD-9-CM
701.9 Skin hypertro/atroph NOS
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 L91.9Overview

Is L91.9 (Hypertrophic disorders of skin) a billable code?

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

What MS-DRG does L91.9 group to?

When hypertrophic disorder of the skin, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, with relative weights from 0.9064 to 1.5132 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of L91.9?

Under the General Equivalence Mappings, hypertrophic disorder of the skin, unspecified converts to ICD-9-CM 701.9 (skin hypertro/atroph NOS). 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.