ICD-10 Code C43 – Malignant Melanoma of Skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C43 – Malignant melanoma of skin
What it is
C43 identifies a malignant melanoma arising in the skin. Use it when the record documents a primary skin melanoma, with the site-specific subcode chosen by anatomic location.
Clinical signs
Common findings include a changing pigmented lesion, asymmetry, irregular borders, color variation, or a lesion that enlarges or bleeds. Clinical features vary; refer to documentation.
When to use this code
Use C43 when the provider diagnoses melanoma of the skin and the documentation supports a primary cutaneous malignancy. Select the most specific subcategory for the body site when available. If the note only says “melanoma” without a site, check documentation before coding.
Do not use for
Do not use this code for benign nevi, melanoma in situ, or metastatic disease to the skin from another primary site. Check documentation if the lesion site or behavior is unclear.
Coding tip
Always code the documented anatomic site and verify whether the melanoma is primary skin disease or another diagnosis.