ICD-10 Code D03.9 – Melanoma in situ, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D03.9 – Melanoma in situ, unspecified
What it is
D03.9 identifies melanoma in situ when the site is not specified. It means malignant melanocytic cells are confined to the epidermis and have not invaded deeper tissue.
Clinical signs
Clinical features vary; refer to documentation. Typical notes describe an atypical pigmented lesion with irregular color, border, or shape, confirmed by pathology as melanoma in situ.
When to use this code
Use D03.9 when the pathology or provider documents melanoma in situ and does not name a specific anatomic site. It is appropriate for confirmed in situ disease before any invasive component is reported. If the chart names the location, choose the more specific code.
Do not use for
Do not use this code for invasive melanoma, dysplastic nevus, or other non-melanoma skin lesions. If documentation is incomplete or the diagnosis is uncertain, check documentation before coding.
Coding tip
Confirm that “in situ” is explicitly documented and that no site-specific code applies.