ICD-10 Code C43.5 – Malignant melanoma of trunk (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C43.5 – Malignant melanoma of trunk
What it is
C43.5 identifies a malignant melanoma arising on the trunk, including the chest, abdomen, back, or flank. Use it when the record documents a primary melanoma in that body area.
Clinical signs
Typical findings include a suspicious pigmented or changing skin lesion with asymmetry, irregular borders, color variation, or enlargement. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents malignant melanoma located on the trunk and the site is not described elsewhere. It applies to the primary lesion on the trunk, not to metastatic disease or a history of melanoma. If the note only says “skin cancer” or the site is unclear, check documentation.
Do not use for
Do not use C43.5 for melanoma of the head, neck, limbs, or other specified skin sites. Do not assign it for non-malignant pigmented lesions or when documentation does not support melanoma.
Coding tip
Verify the exact anatomic site in the pathology or provider note before coding, because melanoma codes are site-specific.