ICD-10 Code C06.89 – Malignant neoplasm of overlapping sites of other parts of mouth (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C06.89 – Malignant neoplasm of overlapping sites of other parts of mouth
What it is
C06.89 identifies a malignant tumor arising in overlapping sites of other specified parts of the mouth. Use this code when the cancer spans more than one oral subsite and documentation does not fit a more specific mouth location.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include an oral mass, ulceration, pain, bleeding, or difficulty chewing or speaking, but the exact presentation depends on the tumor site and extent.
When to use this code
Use this code when the provider documents a malignant neoplasm involving overlapping areas of the mouth, such as a lesion crossing boundaries between adjacent oral structures. It is appropriate when a more specific oral site is not documented. Check the record for the exact anatomic location before coding.
Do not use for
Do not use this code for benign oral lesions, non-overlapping mouth cancers with a more specific site code, or cancers clearly documented in another head and neck location. If the site is unclear, check documentation.
Coding tip
Confirm that the documentation supports an overlapping oral site before assigning C06.89.