2026 ICD-10-CM Diagnosis Code C01Malignant neoplasm of base of tongue
ICD-10-CM Codes›C00–D49›C00-C14›C01
- Billable — Valid for Submission
- Chronic Condition
C01 is a billable ICD-10-CM diagnosis code for malignant neoplasm of base of tongue. 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 - lip and oral cavity.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Carcinoma of base of tongue
- Carcinoma of tongue base - dorsal surface
- Malignant neoplasm of base of tongue
- Malignant neoplasm of base of tongue dorsal surface
- Primary carcinoma of base of tongue
- Primary carcinoma of tongue base - dorsal surface
- Primary malignant neoplasm of base of tongue
- Primary malignant neoplasm of dorsal surface of tongue
- Primary squamous cell carcinoma of base of tongue
- Primary tongue carcinoma
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of dorsal surface of base of tongue
- Malignant neoplasm of fixed part of tongue NOS
- Malignant neoplasm of posterior third of tongue
Use Additional Code
- code to identify:
- alcohol abuse and dependence F10
- history of tobacco dependence Z87.891
- tobacco dependence F17
- tobacco use Z72.0
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.
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional 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.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| tongue › base (dorsal surface) | C01 | C79.89 | D00.07 | D10.1 | D37.02 | D49.0 |
| tongue › fixed part NEC | C01 | C79.89 | D00.07 | D10.1 | D37.02 | D49.0 |
| tongue › posterior (third) | C01 | C79.89 | D00.07 | D10.1 | D37.02 | D49.0 |
| tongue › root | C01 | C79.89 | D00.07 | D10.1 | D37.02 | D49.0 |
| tongue › surface (dorsal) › base | C01 | C79.89 | D00.07 | D10.1 | D37.02 | D49.0 |
Patient EducationClinical
Oral Cancer
Oral cancer is cancer of the mouth. It is a type of head and neck cancer. Most oral cancers are squamous cell cancers. They begin in the flat cells that cover the surfaces of your mouth, tongue, and lips. The cancer cells may spread into deeper tissue as the cancer grows.
The full article covers:
- What is oral cancer?
- Who is more likely to develop oral cancer?
- What are the symptoms of oral cancer?
- How is oral cancer diagnosed?
- What are the treatments for oral cancer?
- Can oral cancer be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C01 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C01Overview
Is C01 (Malignant neoplasm of base of tongue) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of base of tongue on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C01 group to?
When malignant neoplasm of base of tongue 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 C01?
Under the General Equivalence Mappings, malignant neoplasm of base of tongue converts to ICD-9-CM 141.0 (mal neo tongue base). The mapping is a direct match.
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.
