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ICD-10-CM 2027 diagnosis code

C03Malignant neoplasm of gum

Not billable — use a more specific code

C03 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About C03

C03 is the ICD-10-CM diagnosis code for malignant neoplasm of gum. It belongs to block C00-C14 (malignant neoplasms of lip, oral cavity and pharynx) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: C03.0 (gum), C03.1 (gum) and C03.9 (unspecified).

The conditions in its Excludes2 note aren't part of C03, but may be coded alongside it if the patient has both: malignant odontogenic neoplasms (C41.0-C41.1).

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

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under C03

Coding notes

IncludesFurther defines the content of the category
  • malignant neoplasm of alveolar (ridge) mucosa
  • malignant neoplasm of gingiva
Excludes2Not included here — may be reported together if both conditions exist
Use additional codeAdd a secondary code 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 that apply from higher levels

Instructions written at a parent level also apply to C03.

Broader instructions also apply from Chapter 2: Neoplasms.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about C03

Is C03 billable?

No. C03 is a header code. Report one of its more specific subcodes instead.