ICD-10 Code C43.59 – Malignant melanoma of other part of trunk (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C43.59 – Malignant melanoma of other part of trunk
What it is
C43.59 identifies a malignant melanoma located on another specified part of the trunk, such as the chest, abdomen, back, or flank when not captured by a more specific trunk site. Use this code for a confirmed melanoma diagnosis, not for suspicious skin lesions.
Clinical signs
Clinical features vary; refer to documentation. Melanoma is often described as an irregularly pigmented skin lesion with asymmetry, uneven borders, color variation, or change in size, shape, or symptoms. Pathology or clinician documentation should confirm malignancy and site.
When to use this code
Use C43.59 when the provider documents malignant melanoma on a trunk site other than the chest wall, abdomen, or other more specific coded locations. This applies after biopsy, excision, or oncology evaluation confirms the diagnosis. If the exact trunk subsite is unclear, check documentation before coding.
Do not use for
Do not use this code for benign nevi, dysplastic nevi, melanoma in situ, or uncertain skin lesions. Also avoid it when the record specifies a different body site or a more exact trunk location.
Coding tip
Verify the pathology report and the exact anatomic site before assigning C43.59.