ICD-10 Code D04.20 – Carcinoma in situ of skin of unspecified ear and external auricular canal (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D04.20 – Carcinoma in situ of skin of unspecified ear and external auricular canal
What it is
D04.20 identifies carcinoma in situ of the skin on the ear or external auricular canal when the site is not further specified. The abnormal cells are confined to the epidermis and have not invaded deeper tissue.
Clinical signs
Clinical features vary; refer to documentation. You may see a persistent scaly, crusted, or erythematous lesion on the ear, sometimes with a nonhealing or irregular surface.
When to use this code
Use this code when the provider documents carcinoma in situ involving the skin of the ear or external auricular canal and does not name a more specific ear subsite. It also fits pathology-confirmed in situ disease without invasion. If the record states a specific ear location, code that more precise site instead.
Do not use for
Do not use D04.20 for invasive skin cancer, benign lesions, or lesions of a different ear structure. Check documentation if the site is described as auricle, external ear canal, or another specified ear subsite.
Coding tip
Query the provider when the pathology report says “in situ” but the ear site is unclear or conflicts with the operative note.