2027 ICD-10-CM Diagnosis Code L91.0Hypertrophic scar

ICD-10-CM Codes›L00–L99›L80-L99›L91

ICD-10-CM L91.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

L91.0 is a billable ICD-10-CM diagnosis code for hypertrophic scar. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 606 through 607. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified skin disorders.

Code Identity

ICD-10-CM Code
L91.0
Billable Status
Yes — Valid for Submission
Code Describes
Hypertrophic scar
Short Description
Hypertrophic scar
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 CodeL91.0Hypertrophic scar

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acne scar
  • Acne scars - mixed atrophic and hypertrophic
  • Acroosteolysis
  • Acroosteolysis, keloid-like lesions, premature aging syndrome
  • Contracture scar
  • Disorder of skin donor site
  • Ear-lobe keloid
  • Hereditary acroosteolysis
  • Hypertrophic acne scar
  • Hypertrophic scar
  • Hypertrophic scar of upper arm
  • Hypertrophic scarring of skin donor site
  • Hypertrophic surgical scar
  • Keloid acne scar
  • Keloid scar
  • Keloidal surgical scar
  • Surgical scar finding
  • X-linked keloid scarring, reduced joint mobility, increased optic cup-to-disc ratio syndrome

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to L91.0: its own notes plus those printed at Chapter 12. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Keloid
  • Keloid scar

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On L91.0 itself
From Chapter 12 (L00-L99) Diseases of the skin and subcutaneous tissue applies to 1,001 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • lipomelanotic reticulosis (I89.8)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • viral warts (B07.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name L91.0, its category, or a range that includes it.

Excludes2 3

These codes carry an Excludes2 note naming L91.0: its condition is not part of those codes, and both may be reported when the patient has both.

  • L90.5 Scar conditions and fibrosis of skin
    hypertrophic scar (L91.0)
  • L90.5 Scar conditions and fibrosis of skin
    keloid scar (L91.0)
  • L85 Other epidermal thickening
    hypertrophic disorders of the skin (L91.-) names L91.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Clinical InformationClinical

  • Cicatrix, Hypertrophic

    an elevated scar, resembling a keloid, but which does not spread into surrounding tissues. it is formed by enlargement and overgrowth of cicatricial tissue and regresses spontaneously.

Patient EducationClinical

Scars

A scar is a permanent patch of skin that grows over a wound. It forms when your body heals itself after a cut, scrape, burn, or sore. You can also get scars from surgery that cuts through the skin, infections like chickenpox, or skin conditions like acne.

Read the full article at MedlinePlus

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

Convert L91.0 to ICD-9-CMHistory

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

ICD-9-CM
701.4 Keloid scar
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About L91.0Overview

What is the ICD-10 code for hypertrophic scar?

The ICD-10-CM code for hypertrophic scar is L91.0 (sometimes written as L910). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is L91.0 (Hypertrophic disorders of skin) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report hypertrophic scar on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does L91.0 group to?

When hypertrophic scar is the principal diagnosis on an inpatient stay, it groups to MS-DRG 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of L91.0?

Under the General Equivalence Mappings, hypertrophic scar converts to ICD-9-CM 701.4 (keloid scar). The mapping is a direct match.