Melanoma in situ of left upper eyelid, including canthus

This code signifies the presence of melanoma that is confined to the epidermis (in situ) on the left upper eyelid, including any involvement of the canthus. This is a non-invasive form of skin cancer, meaning it has not spread beyond the outermost layer of skin.

Use this code when diagnostic pathology reports confirm melanoma in situ specifically located on the left upper eyelid or its associated canthus. Documentation should clearly specify the lesion's location and the in situ nature of the melanoma.

• Ensure the pathology report explicitly states "melanoma in situ" and specifies the left upper eyelid, including or excluding the canthus.
• Do not use this code for invasive melanoma; a different code from the C43 series would be appropriate for invasive forms.
• Laterality is crucial; verify the documentation specifies "left" upper eyelid.