Malignant neoplasm of base of tongue
In Malignant neoplasms of lip, oral cavity and pharynx (C00-C14), chapter 2: Neoplasms
- C01 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under C00-C14 below.
- As a secondary diagnosis it is not a CC or MCC, so it doesn't raise the MS-DRG payment.
- Counts toward HCC 21 (Lymphoma and Other Cancers) in the Medicare Advantage risk model (CMS-HCC V28).
- AHRQ's Chronic Condition Indicator classes it as chronic: expected to last 12 months or longer and to limit daily life or need ongoing care.
- 322 US deaths in 2024 had an underlying cause in category C01, per the National Vital Statistics System on CDC WONDER. Death records use WHO ICD-10, so the count is for the whole category.
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Instructional notes
Includes: conditions that are coded here
- Malignant neoplasm of dorsal surface of base of tongue
- Malignant neoplasm of fixed part of tongue NOS
- Malignant neoplasm of posterior third of tongue
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Rules for coding benign and malignant neoplasms: using the Neoplasm Table, sequencing primary and secondary sites, treatment encounters, complications, and current cancer versus personal history.
- Admission/Encounter for treatment of primary site (page 33)
- Admission/Encounter for treatment of secondary site (page 33)
- Coding and sequencing of complications (page 34)
- Primary malignancy previously excised (page 34)
- Admissions/Encounters involving antineoplastic chemotherapy, immunotherapy and radiation therapy (page 35)
- Admission/encounter to determine extent of malignancy (page 36)
- Symptoms, signs, and abnormal findings listed in Chapter 18 associated with neoplasms (page 36)
- Admission/encounter for pain control/management (page 36)
Other codes under C00-C14
Malignant neoplasms of lip, oral cavity and pharynx (C00-C14)
- C00Malignant neoplasm of lip
- C01Malignant neoplasm of base of tongue(this code)
- C02Malignant neoplasm of other and unspecified parts of tongue
- C03Malignant neoplasm of gum
- C04Malignant neoplasm of floor of mouth
- C05Malignant neoplasm of palate
- C06Malignant neoplasm of other and unspecified parts of mouth
- C07Malignant neoplasm of parotid gland
- C08Malignant neoplasm of other and unspecified major salivary glands
- C09Malignant neoplasm of tonsil
- C10Malignant neoplasm of oropharynx
- C11Malignant neoplasm of nasopharynx
- C12Malignant neoplasm of pyriform sinus
- C13Malignant neoplasm of hypopharynx
- C14Malignant neoplasm of other and ill-defined sites in the lip, oral cavity and pharynx
C01 MS-DRGs
This code does not group to an MS-DRG as a principal diagnosis.
Related conditions
Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.
C01 is in Head and neck cancers - lip and oral cavity (NEO002, its default category), with 43 codes. Others in it:
- C00.0 Malignant neoplasm of external upper lip
- C00.1 Malignant neoplasm of external lower lip
- C00.2 Malignant neoplasm of external lip, unspecified
- C00.3 Malignant neoplasm of upper lip, inner aspect
- C00.4 Malignant neoplasm of lower lip, inner aspect
- C00.5 Malignant neoplasm of lip, unspecified, inner aspect
- C00.6 Malignant neoplasm of commissure of lip, unspecified
- C00.8 Malignant neoplasm of overlapping sites of lip
Medicare coverage articles listing C01
These 31 Medicare billing and coding articles list C01 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.
- MolDX: Genetic Testing for Hereditary Thrombophilia (4 contractors)
- MolDX: Minimal Residual Disease Testing for Solid Tumor Cancers (4 contractors)
- MolDX: Next-Generation Sequencing for Solid Tumors (4 contractors)
- MolDX: Non-Next Generation Sequencing Targeted Molecular Panel Tests for Targeted Therapy in Cancer (4 contractors)
- MolDX: Plasma-Based Genomic Profiling in Solid Tumors (4 contractors)
- MolDX: Lab-Developed Tests for Inherited Cancer Syndromes in Patients with Cancer (3 contractors)
- Erythropoiesis Stimulating Agents (2 contractors)
- Peripheral Nerve Blocks (2 contractors)
- Proton Beam Therapy
- Cardiac Blood Pool Imaging (Multiple Gated Acquisition Scanning- MUGA, Ventriculography) When Performed in Conjunction with Cardiotoxic Chemotherapy
And 21 more.
Other codes that refer to C01
Notes on these codes point to C01.
- C02.0 Excludes2: malignant neoplasm of dorsal surface of base of tongue (C01)
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
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.
Read more about oral cancer on MedlinePlusCode history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.
ICD-9-CM equivalent
Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).
- 141.0 Malignant neoplasm of base of tongue