ICD-10 Code C06 – Malignant neoplasm of other and unspecified parts of mouth (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C06 – Malignant neoplasm of other and unspecified parts of mouth
What it is
C06 identifies a malignant tumor arising in other specified or unspecified parts of the mouth. Use it when the record documents oral cancer outside the lip, tongue, gum, floor of mouth, palate, or other more specific oral sites.
Clinical signs
Clinical features vary; refer to documentation. Oral malignancies may present as a persistent ulcer, mass, pain, bleeding, or difficulty chewing or speaking, but the exact site must be confirmed in the chart.
When to use this code
Use C06 when the provider documents a malignant neoplasm in a mouth site that is not more specifically classified, or when the note states an unspecified part of the mouth. It is appropriate for confirmed primary oral cancer diagnoses. If the site is named more precisely, code that specific subcategory instead.
Do not use for
Do not use C06 for benign oral lesions, dysplasia, or cancers clearly documented in another oral structure such as the lip or tongue. Check documentation if the exact anatomic site is unclear.
Coding tip
Query the clinician when the record says only “oral cancer” or “mouth lesion” without a definitive malignant site.