C00.4 Malignant neoplasm of lower lip, inner aspect

The ICD-10-CM code for Malignant neoplasm of lower lip, inner aspect is C00.4 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C00-C14: Malignant neoplasms of lip, oral cavity and pharynx (C00-C14)

Category C00

10 codes (9 billable)

FY2026 Status

Stable since FY2024

Inclusion Terms

• Malignant neoplasm of buccal aspect of lower lip
• Malignant neoplasm of frenulum of lower lip
• Malignant neoplasm of mucosa of lower lip
• Malignant neoplasm of oral aspect of lower lip

U.S. Hospital Utilization

• An estimated 65 U.S. inpatient stays in 2019 included C00.4 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Chapter 2 TOC entry

2. Chapter 2: Neoplasms (C00-D49) .......................................................................................... 32

Chapter 2 contains codes for most benign and all malignant neoplasms

2. Chapter 2: Neoplasms (C00-D49) General Guidelines Chapter 2 of the ICD-10-CM contains the codes for most benign and all malignant neoplasms. Certain benign neoplasms, such as prostatic adenomas, may be found in the

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)