2026 ICD-10-CM Diagnosis Code D03.9Melanoma in situ, unspecified

ICD-10-CM Codes›C00–D49›D00-D09›D03

ICD-10-CM D03.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D03.9 is a billable ICD-10-CM diagnosis code for melanoma in situ, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 595 through 596. Coders also document this condition as in situ acral lentiginous malignant melanoma. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Skin cancers - melanoma.

Code Identity

ICD-10-CM Code
D03.9
Billable Status
Yes — Valid for Submission
Code Describes
Melanoma in situ, unspecified
Short Description
Melanoma in situ, unspecified
Same as the full description in the CMS dataset.
Parent Code
D03
Melanoma in situ

Code Classification

ChapterC00–D49Neoplasms
SectionD00-D09In situ neoplasms
CategoryD03Melanoma in situ
This CodeD03.9Melanoma in situ, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • In situ acral lentiginous malignant melanoma
  • Lentigo maligna
  • Melanoma in situ
  • Melanoma in situ of non-skin site
  • Melanoma in situ of skin
  • Precancerous melanosis
  • Surgical lateral margin involved by in situ melanoma
  • Surgical lateral margin uninvolved by in situ melanoma

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.

    • Melanoma(malignant)
      • in situ
    • Melanoma(malignant)
      • in situ
        • nail

Clinical ClassificationClinical

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

CCSR NEO025
Skin cancers - melanoma
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Melanoma

Melanoma is the most serious type of skin cancer. Often the first sign of melanoma is a change in the size, shape, color, or feel of a mole. Most melanomas have a black or black-blue area. Melanoma may also appear as a new mole. It may be black, abnormal, or "ugly looking."

Read the full article at MedlinePlus

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

Convert D03.9 to ICD-9-CMHistory

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

ICD-9-CM
172.9 Malig melanoma skin 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 D03.9Overview

Is D03.9 (Melanoma in situ) a billable code?

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

What MS-DRG does D03.9 group to?

When melanoma in situ, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 595, 596, with relative weights from 1.0825 to 2.1207 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D03.9?

Under the General Equivalence Mappings, melanoma in situ, unspecified converts to ICD-9-CM 172.9 (malig melanoma skin NOS). The mapping is approximate, so confirm the match fits the documentation.

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.