ICD-10 Code D04.12 – Carcinoma in situ of skin of left eyelid, including canthus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D04.12 – Carcinoma in situ of skin of left eyelid, including canthus
What it is
D04.12 identifies carcinoma in situ limited to the skin of the left eyelid, including the canthus. The abnormal cells have not invaded deeper tissue, but they require prompt documentation and follow-up.
Clinical signs
Clinical features vary; refer to documentation. Typical records may describe a localized eyelid lesion, often suspicious for malignancy on exam or biopsy, without evidence of invasion beyond the skin.
When to use this code
Use this code when the provider documents carcinoma in situ specifically on the left eyelid or left canthus. It also fits pathology-confirmed in situ disease when the site is clearly stated in the record.
If the note only says “eyelid lesion” or gives an unspecified side, check documentation before coding. Make sure the diagnosis is in situ, not invasive skin cancer or a different eyelid disorder.
Do not use for
Do not use D04.12 for invasive eyelid skin cancers, benign eyelid lesions, or lesions on the right eyelid. If the site or diagnosis is unclear, check documentation.
Coding tip
Confirm both laterality and “in situ” wording in the provider note or pathology report before assigning D04.12.