2027 ICD-10-CM Diagnosis Code C04Malignant neoplasm of floor of mouth

ICD-10-CM Codes›C00–D49›C00-C14›C04

ICD-10-CM C04
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

C04 is a non-billable ICD-10-CM category code for malignant neoplasm of floor of mouth, so it cannot be submitted on claims. Use a more specific code from this category instead, such as C04.0, C04.1, C04.8, and C04.9.

Code Identity

ICD-10-CM Code
C04
Billable Status
No — Non-Billable Category
Code Describes
Malignant neoplasm of floor of mouth
Short Description
Malignant neoplasm of floor of mouth
Same as the full description in the CMS dataset.
Chapter
C00-C14
Malignant neoplasms of lip, oral cavity and pharynx

Code Classification

ChapterC00–D49Neoplasms
SectionC00-C14Malignant neoplasms of lip, oral cavity and pharynx
CategoryC04Malignant neoplasm of floor of mouth
This CodeC04Malignant neoplasm of floor of mouth

Specific Coding for Malignant neoplasm of floor of mouthOverview

Non-specific codes like C04 require more characters. Use one of these billable codes instead:

  • Use C04.0 for Malignant neoplasm of anterior floor of mouth

  • Use C04.1 for Malignant neoplasm of lateral floor of mouth

  • Use C04.8 for Malignant neoplasm of overlapping sites of floor of mouth

  • Use C04.9 for Malignant neoplasm of floor of mouth, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C04: its own notes plus those printed at Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Use Additional Code

Add a second code, after this one, to fully describe the condition.

  • code to identify:
  • alcohol abuse and dependence (F10.-)
  • history of tobacco dependence (Z87.891)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Notes

General instructions on how these codes are used.

From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name C04, its category, or a range that includes it.

Applicable To 3

These notes mention C04.

  • Z80.8 Family history of malignant neoplasm of other organs or systems
    Conditions classifiable to C00-C14, C40-C49, C69-C79 names C00-C14, which includes this code
  • Z85.8 Personal history of malignant neoplasms of other organs and systems
    Conditions classifiable to C00-C14, C40-C49, C69-C75, C7A.098, C76-C79 names C00-C14, which includes this code
  • Z85.81 Personal history of malignant neoplasm of lip, oral cavity, and pharynx
    Conditions classifiable to C00-C14 names C00-C14, which includes this code

Clinical InformationClinical

  • Malignant Floor of the Mouth Neoplasm

    a primary or metastatic malignant neoplasm that affects the floor of the mouth. the majority of cases are carcinomas.

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.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About C04Overview

What is the ICD-10 code for malignant neoplasm of floor of mouth?

C04 is the ICD-10-CM category for malignant neoplasm of floor of mouth, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is C04 (Malignant neoplasm of floor of mouth) a billable code?

No. This is a category header that groups the codes for malignant neoplasm of floor of mouth, and headers cannot be submitted on claims. Claims for malignant neoplasm of floor of mouth need a more specific code from this category, such as C04.0, C04.1, and C04.8.

Does C04 need an additional code?

When the condition applies, yes. The Use Additional Code note reads: code to identify: alcohol abuse and dependence (F10.-); history of tobacco dependence (Z87.891); tobacco dependence (F17.-); tobacco use (Z72.0). The additional code is reported after C04.