ICD-10 Code D04.21 – Carcinoma in situ of skin of right ear and external auricular canal (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D04.21 – Carcinoma in situ of skin of right ear and external auricular canal
What it is
D04.21 identifies carcinoma in situ limited to the skin of the right ear and external auricular canal. The abnormal cells have not invaded deeper tissue, so you should code a localized in situ lesion.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records describe a suspicious or biopsy-confirmed noninvasive skin lesion on the right ear or ear canal, often noted as carcinoma in situ.
When to use this code
Use this code when the provider documents carcinoma in situ specifically involving the right ear or external auricular canal. It is appropriate after pathology or specialist assessment confirms the lesion is in situ and right-sided.
Choose this code when the site is clearly documented and no invasive skin cancer is reported. If the note only says “ear lesion” or laterality is missing, check documentation before assigning D04.21.
Do not use for
Do not use D04.21 for invasive skin cancer, benign ear lesions, or unspecified ear sites. If the lesion is on the left ear or another skin location, select the matching code.
Coding tip
Verify both laterality and that the diagnosis is truly in situ before coding; if either is unclear, query the provider.