ICD-10 Code C43.122 – Malignant melanoma of left lower eyelid, including canthus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C43.122 – Malignant melanoma of left lower eyelid, including canthus
What it is
C43.122 identifies a malignant melanoma arising on the left lower eyelid, including the canthus. Use it when documentation specifies this exact anatomic site and a melanoma diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include a pigmented or changing eyelid lesion, irregular borders, ulceration, or local enlargement noted on exam or biopsy.
When to use this code
Use this code when the provider documents malignant melanoma of the left lower eyelid or left lower lid with canthal involvement. It is appropriate for confirmed primary melanoma at this site, including pathology-supported diagnoses.
If the record only says “eyelid melanoma” without laterality or eyelid location, check documentation before assigning C43.122. Make sure the lesion is on the left lower eyelid, not another eyelid or periocular skin site.
Do not use for
Do not use C43.122 for benign eyelid lesions, melanoma in situ, or melanoma at a different eyelid location. Check documentation if the site is unspecified or if the lesion involves another periocular structure.
Coding tip
Verify laterality and exact eyelid site in the operative note, pathology report, or assessment before coding.