ICD-10 Code C06.9 – Malignant neoplasm of mouth, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C06.9 – Malignant neoplasm of mouth, unspecified
What it is
C06.9 identifies a malignant tumor in the mouth when the exact oral site is not documented. Use it for a confirmed cancer of the oral cavity without a more specific location.
Clinical signs
Clinical features vary; refer to documentation. Oral cancers may present with a persistent mouth lesion, ulcer, mass, pain, bleeding, or difficulty chewing or speaking, but the recorded diagnosis should drive coding.
When to use this code
Use C06.9 when the provider documents malignant neoplasm of the mouth and does not specify the precise subsite, such as lip, tongue, gum, or palate. It also fits when the chart confirms oral cancer but the location remains unspecified after review.
Do not use for
Do not use this code for benign oral lesions, dysplasia, or cancers with a documented specific oral subsite. If the record names a more exact site, code that site instead.
Coding tip
Check the pathology, operative note, and assessment for a more specific oral site before defaulting to unspecified.