2026 ICD-10-CM Diagnosis Code C09.9Malignant neoplasm of tonsil, unspecified
ICD-10-CM Codes›C00–D49›C00-C14›C09
- Billable — Valid for Submission
- Chronic Condition
C09.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of tonsil, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 146 through 148. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - tonsils.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Malignant neoplasm of tonsil
- Primary malignant neoplasm of lateral wall of oropharynx
- Primary malignant neoplasm of tonsil
- Primary malignant neoplasm of Waldeyer's ring
- Primary squamous cell carcinoma of lateral wall of oropharynx
- Primary squamous cell carcinoma of palatine tonsil
- Primary squamous cell carcinoma of Waldeyer ring
- Primary tonsil carcinoma
- Squamous cell carcinoma of lateral wall of oropharynx
- Tonsil carcinoma
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of tonsil NOS
- Malignant neoplasm of faucial tonsils
- Malignant neoplasm of palatine tonsils
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
Patient EducationClinical
Throat Cancer
Throat cancer is a type of head and neck cancer. Throat cancer has different names, depending on which part of the throat is affected. The different parts of your throat are called the oropharynx, the hypopharynx, the nasopharynx, and the larynx, or voice box.
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Convert C09.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C09.9Overview
Is C09.9 (Malignant neoplasm of tonsil) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of tonsil, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C09.9 group to?
When malignant neoplasm of tonsil, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 146, 147, 148, with relative weights from 0.7971 to 2.1174 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C09.9?
Under the General Equivalence Mappings, malignant neoplasm of tonsil, unspecified converts to ICD-9-CM 146.0 (malignant neopl tonsil). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
