ICD-10 Code C43.1 – Malignant melanoma of eyelid, including canthus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C43.1 – Malignant melanoma of eyelid, including canthus
What it is
C43.1 identifies a malignant melanoma arising in the eyelid or canthus. Use it when the documentation clearly states melanoma in this periocular skin area.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include a changing pigmented eyelid lesion, asymmetry, irregular borders, or color variation, but the diagnosis should be confirmed by pathology when available.
When to use this code
Use C43.1 when the provider documents malignant melanoma of the eyelid, including the inner or outer canthus. It also fits cases where pathology or operative notes specify this site as the primary tumor location. If the record only says “melanoma” without site, check documentation.
Do not use for
Do not use this code for benign eyelid lesions, nonmelanoma skin cancers, or melanoma at another anatomic site. Check documentation if the note describes conjunctival, orbital, or unspecified skin involvement.
Coding tip
Confirm the exact eyelid/canthus site and whether the melanoma is primary there before assigning C43.1.