ICD-10 Code C06.80 – Malignant neoplasm of overlapping sites of unspecified parts of mouth (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C06.80 – Malignant neoplasm of overlapping sites of unspecified parts of mouth
What it is
This code identifies a malignant tumor involving overlapping sites in unspecified parts of the mouth. Use it when the documentation confirms oral cancer but does not name a single, more specific mouth subsite.
Clinical signs
Clinical features vary; refer to documentation. Common findings in oral malignancy include a persistent oral lesion, ulceration, pain, bleeding, or difficulty chewing or speaking.
When to use this code
Use C06.80 when the provider documents a malignant neoplasm of the mouth and the lesion spans overlapping oral sites, but the exact anatomic site is not further specified. It also fits when the record confirms oral cancer without enough detail for a more specific code.
Do not use for
Do not use this code for benign oral lesions, dysplasia, or cancers with a clearly documented single site such as lip, tongue, gum, or palate. Check documentation if the primary site is named elsewhere.
Coding tip
Query for the exact oral subsite when the note says “mouth cancer” without location detail.