ICD-10 Code D00.01 – Carcinoma in situ of labial mucosa and vermilion border (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D00.01 – Carcinoma in situ of labial mucosa and vermilion border
What it is
This code identifies carcinoma in situ limited to the labial mucosa or vermilion border of the lip. It means abnormal cells are present in the surface layer and have not invaded deeper tissue.
Clinical signs
Findings may include a persistent lip lesion, plaque, erythema, ulceration, or leukoplakia. Clinical features vary; refer to documentation and pathology for confirmation.
When to use this code
Use D00.01 when the provider documents carcinoma in situ of the labial mucosa or vermilion border, including biopsy-confirmed noninvasive disease. Code it when the site is clearly specified as the lip mucosa or vermilion border.
If the record only says “lip cancer” or gives an uncertain site, check documentation before assigning this code. Confirm that the diagnosis is in situ rather than invasive.
Do not use for
Do not use this code for invasive malignant neoplasm of the lip or for lesions on other oral sites. Check documentation if the site is the skin of the lip rather than the mucosa or vermilion border.
Coding tip
Verify both the exact lip subsite and the in situ wording in the pathology or provider note before coding.