C43.9 Malignant melanoma of skin, unspecified

The ICD-10-CM code for Malignant melanoma of skin, unspecified is C43.9 (FY2026). It is a billable, claim-ready diagnosis code.

Choosing between codes? See the guide: ICD-10 code for melanoma.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C43-C44: Melanoma and other malignant neoplasms of skin (C43-C44)

Category C43

33 codes (24 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to C43.9:

• Melanoma (malignant)
• Melanoma (malignant) › skin
• Melanoma (malignant) › skin › skin NEC

Inclusion Terms

• Malignant melanoma of unspecified site of skin
• Melanoma (malignant) NOS

U.S. Hospital Utilization

• An estimated 19,175 U.S. inpatient stays in 2023 included C43.9 among the documented diagnoses.
• 520 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Prevalence & Statistics

• In 2023, an estimated 1,573,288 people in the United States were living with melanoma of the skin. (NCI SEER Cancer Stat Facts: Melanoma of the Skin, 2023)

Official Coding Guidelines

Tx of primary site (TOC entry)

a. Admission/Encounter for treatment of primary site ............................................................. 33

Tx of secondary site (TOC entry)

b. Admission/Encounter for treatment of secondary site .......................................................... 33

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)
• NCI SEER Cancer Stat Facts: Melanoma of the Skin (2023)

Cite This Page

Reference C43.9 with the canonical source and edition:

C43.9 — Malignant melanoma of skin, unspecified. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/C43.9

Canonical URL: https://icd10codingpro.com/codes/C43.9