C31.0 Malignant neoplasm of maxillary sinus

The ICD-10-CM code for Malignant neoplasm of maxillary sinus is C31.0 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C30-C39: Malignant neoplasms of respiratory and intrathoracic organs (C30-C39)

Category C31

7 codes (6 billable)

FY2026 Status

Stable since FY2024

Inclusion Terms

• Malignant neoplasm of antrum (Highmore) (maxillary)

U.S. Hospital Utilization

• An estimated 1,460 U.S. inpatient stays in 2023 included C31.0 among the documented diagnoses.
• 575 stays listed it as the principal diagnosis.

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

Tx of primary site (TOC entry)

a. Admission/Encounter for treatment of primary site ............................................................. 33

Tx of secondary site (TOC entry)

b. Admission/Encounter for treatment of secondary site .......................................................... 33

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)