ICD10
ICD-10 Code C04: Malignant neoplasm of floor of mouth
Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026
What is this code?
ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).
When is it used?
- May be used when a clinician documents malignant neoplasm of floor of mouth in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
- This entry may represent a broader category rather than the most specific billable code.
Code hierarchy
chapter
2Neoplasms (C00-D49)
block
C00-C96Malignant neoplasms
block
C00-C75Malignant neoplasms, stated or presumed to be primary (of specified sites), and certain specified histologies, except neuroendocrine, and of lymphoid, hematopoietic and related tissue
block
C00-C14Malignant neoplasms of lip, oral cavity and pharynx
currentC00-C14
Official coding notes
Applicable to
- code to identify:
- alcohol abuse and dependence (F10.-)
- history of tobacco dependence (Z87.891)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
Use additional code
- code to identify:
- alcohol abuse and dependence (F10.-)
- history of tobacco dependence (Z87.891)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
Where you may see this code
You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.
Related specialists
OncologistGeneral Physician
Related codes
Sibling codes
C00Malignant neoplasm of lipC01Malignant neoplasm of base of tonguebillableC02Malignant neoplasm of other and unspecified parts of tongueC03Malignant neoplasm of gumC05Malignant neoplasm of palateC06Malignant neoplasm of other and unspecified parts of mouthC07Malignant neoplasm of parotid glandbillableC08Malignant neoplasm of other and unspecified major salivary glandsC09Malignant neoplasm of tonsilC10Malignant neoplasm of oropharynxC11Malignant neoplasm of nasopharynxC12Malignant neoplasm of pyriform sinusbillableC13Malignant neoplasm of hypopharynxC14Malignant neoplasm of other and ill-defined sites in the lip, oral cavity and pharynx
Coding guidelines
Compatibility
Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.
Legacy codes
C04
Replacement codes
C04.0 — Malignant neoplasm of anterior floor of mouthC04.1 — Malignant neoplasm of lateral floor of mouthC04.8 — Malignant neoplasm of overlapping sites of floor of mouthC04.9 — Malignant neoplasm of floor of mouth, unspecified
Common synonyms
Malignant neoplasm of floor of mouth
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.