ICD-10 Code C09.9 – Malignant neoplasm of tonsil, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C09.9 – Malignant neoplasm of tonsil, unspecified
What it is
C09.9 identifies a malignant tumor of the tonsil when the specific tonsillar site is not documented. Use it for a confirmed cancer diagnosis involving the tonsil, but not a more precise tonsil subsite.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a tonsillar mass, sore throat, trouble swallowing, ear pain, or a neck lump, but you should code only what is documented.
When to use this code
Use C09.9 when the record confirms malignant neoplasm of the tonsil and does not specify the exact tonsillar region. It is also appropriate when the provider documents tonsil cancer without further detail. Check documentation if laterality, subsite, or histology is recorded elsewhere.
Do not use for
Do not use this code for benign tonsillar lesions, dysplasia, or infections such as tonsillitis. If the cancer is documented at a more specific tonsillar site, use the more specific code instead.
Coding tip
If the note says “tonsil cancer” only, confirm that no more specific tonsil site is documented before assigning C09.9.