ICD-10 Code C03 – Malignant neoplasm of gum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C03 – Malignant neoplasm of gum
What it is
C03 identifies a malignant tumor arising in the gum tissue. You use it for cancer documented as involving the gingiva, not the lip, tongue, or other oral sites.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include a persistent gum mass, ulceration, bleeding, pain, or loosening of nearby teeth, but the diagnosis must be confirmed in the record.
When to use this code
Use C03 when the provider documents primary malignant neoplasm of the gum or gingiva. It also applies when the chart clearly identifies a gum-origin cancer during evaluation, biopsy, or oncology follow-up. If the site is unclear or another oral structure is named, check documentation before coding.
Do not use for
Do not use C03 for benign gum lesions, dysplasia, or cancers documented in another oral location. If the record only says “oral cancer” without a gum site, check documentation.
Coding tip
Code the exact anatomic site stated by the provider; gingiva and other oral subsites are not interchangeable.