ICD-10 Code C00.0 – Malignant neoplasm of external upper lip (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C00.0 – Malignant neoplasm of external upper lip
What it is
This code identifies a malignant tumor located on the external upper lip. Use it when documentation specifies cancer of the upper lip skin or vermilion rather than the inner lip.
Clinical signs
Clinical features may include a persistent lip lesion, ulceration, induration, bleeding, or a nonhealing sore. Clinical features vary; refer to documentation.
When to use this code
Use C00.0 when the provider documents primary malignant neoplasm of the external upper lip. It also fits pathology or oncology notes that clearly localize the tumor to the outer upper lip. Check documentation if the site is described only as “lip” or is ambiguous.
Do not use for
Do not use this code for malignancies of the inner lip, lip commissure, or other oral cavity sites. If the record does not clearly specify the external upper lip, check documentation.
Coding tip
Confirm the exact lip subsite from the operative, pathology, or oncology note before assigning C00.0.