ICD-10 Code D04.9 – Carcinoma in situ of skin, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D04.9 – Carcinoma in situ of skin, unspecified
What it is
D04.9 identifies a skin cancer confined to the epidermis, with no documented invasion into deeper tissue. Use it when the record states carcinoma in situ of skin but does not specify the site.
Clinical signs
Clinical features vary; refer to documentation. Typical notes may describe a localized, persistent skin lesion suspicious for in situ malignancy, often confirmed by pathology without evidence of invasion.
When to use this code
Use D04.9 when the provider documents carcinoma in situ of skin and the exact anatomic site is not stated. It also fits pathology-confirmed in situ disease when the record remains nonspecific about location. If the site is named, choose the more specific D04 code instead.
Do not use for
Do not use this code for invasive skin cancer or for benign, premalignant, or uncertain lesions. Check documentation if the diagnosis is only “rule out,” “suspicious for,” or if the site is clearly identified.
Coding tip
Query for the exact lesion site before defaulting to D04.9, because unspecified coding is appropriate only when location cannot be determined from the record.