ICD-10 Code D04 – Carcinoma in situ of skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D04 – Carcinoma in situ of skin
What it is
D04 identifies carcinoma in situ of the skin, meaning abnormal cells are confined to the epidermis and have not invaded deeper tissue. Use it when the record clearly states in situ skin cancer.
Clinical signs
Clinical features vary; refer to documentation. Records may describe a localized, noninvasive skin lesion confirmed by pathology or clinician assessment as carcinoma in situ.
When to use this code
Use D04 when the provider documents carcinoma in situ of skin without evidence of invasion. It may apply to lesions diagnosed by biopsy or excision that are specifically reported as in situ. Check the site and pathology wording carefully.
Do not use for
Do not use D04 for invasive skin cancers or for suspicious lesions that are not confirmed as in situ. If the documentation only says “skin cancer” or is unclear, check documentation.
Coding tip
Code the documented site and histology exactly as stated, and confirm that “in situ” is supported by the pathology or provider note.