ICD-10 Code C06.1 – Malignant neoplasm of vestibule of mouth (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C06.1 – Malignant neoplasm of vestibule of mouth
What it is
C06.1 identifies a malignant tumor arising in the vestibule of the mouth, the space between the lips or cheeks and the teeth. Use it when documentation states cancer in this specific oral site.
Clinical signs
Clinical features vary; refer to documentation. Oral cavity cancers may present as a persistent ulcer, mass, pain, bleeding, or difficulty chewing, speaking, or opening the mouth.
When to use this code
Use C06.1 when the provider documents primary malignant neoplasm of the oral vestibule or vestibular mucosa. It also fits pathology-confirmed cancer localized to that site. If the record only says “mouth cancer” without a site, check documentation before coding.
Do not use for
Do not use this code for benign lesions, dysplasia, or cancers located elsewhere in the oral cavity. If the site is the lip, tongue, gum, or another mouth structure, choose the documented location.
Coding tip
Verify the exact anatomic site in the pathology or operative note before assigning C06.1.