ICD-10-CM 2027 diagnosis code
C03.1Malignant neoplasm of lower gum
C03.1 is a valid, billable ICD-10-CM code for malignant neoplasm of lower gum. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS, effective October 1, 2026. Updated September 29, 2026. About our data
About C03.1
C03.1 is the ICD-10-CM diagnosis code for malignant neoplasm of lower gum. It belongs to category C03 (malignant neoplasm of gum), block C00-C14 (malignant neoplasms of lip, oral cavity and pharynx) and chapter 2 (neoplasms). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within C03 (malignant neoplasm of gum), C03.1 is specifically for malignant neoplasm of lower gum. Related codes cover upper gum (C03.0) and unspecified (C03.9).
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 is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC, relative weight 5.6154), DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC, relative weight 4.381), DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC, relative weight 2.7307), DRG 146 (Ear, Nose, Mouth and Throat Malignancy with MCC, relative weight 2.1329), DRG 147 (Ear, Nose, Mouth and Throat Malignancy with CC, relative weight 1.3055) and DRG 148 (Ear, Nose, Mouth and Throat Malignancy without CC/MCC, relative weight 0.8008), in Pre-MDC and MDC 03 (Diseases and Disorders of the Ear, Nose, Mouth and Throat), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 143.1 (malignant neoplasm of lower gum).
Notes that apply from higher levels
Instructions written at a parent level also apply to C03.1.
Broader instructions also apply from Chapter 2: Neoplasms.
Table of Drugs & Neoplasms entries
- Neoplasm, neoplastic › alveolar › mucosa › lower — Malignant Primary
- Neoplasm, neoplastic › alveolar › ridge or process › carcinoma › lower — Malignant Primary
- Neoplasm, neoplastic › alveolar › ridge or process › mucosa › lower — Malignant Primary
- Neoplasm, neoplastic › alveolus › lower — Malignant Primary
- Neoplasm, neoplastic › gingiva (alveolar) (marginal) › lower — Malignant Primary
- Neoplasm, neoplastic › gingiva (alveolar) (marginal) › mandibular — Malignant Primary
- Neoplasm, neoplastic › gum › lower — Malignant Primary
- Neoplasm, neoplastic › interdental papillae › lower — Malignant Primary
- Neoplasm, neoplastic › jaw › soft tissues › lower — Malignant Primary
- Neoplasm, neoplastic › mandible › alveolar › mucosa (carcinoma) — Malignant Primary
- Neoplasm, neoplastic › mucosa › alveolar (ridge or process) › lower — Malignant Primary
Codes whose notes reference C03.1
- C41.1Excludes2
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC PRE · Pre-MDC
MDC 03 · Diseases and Disorders of the Ear, Nose, Mouth and Throat
ICD-9-CM equivalent
Converter →- 143.1Malignant neoplasm of lower gumexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about C03.1
Is C03.1 billable?
- Yes. C03.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can C03.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict C03.1 as a principal diagnosis.
Is C03.1 a CC or MCC?
- No. C03.1 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does C03.1 group to?
- C03.1 is used in the MS-DRG v44.0 logic for MS-DRG 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC), MS-DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC), MS-DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC), MS-DRG 146 (Ear, Nose, Mouth and Throat Malignancy with MCC), MS-DRG 147 (Ear, Nose, Mouth and Throat Malignancy with CC) and MS-DRG 148 (Ear, Nose, Mouth and Throat Malignancy without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for C03.1?
- The CMS General Equivalence Mappings map C03.1 to ICD-9-CM 143.1.