C71.7 Malignant neoplasm of brain stem

The ICD-10-CM code for Malignant neoplasm of brain stem is C71.7 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C69-C72: Malignant neoplasms of eye, brain and other parts of central nervous system (C69-C72)

Category C71

11 codes (10 billable)

FY2026 Status

Stable since FY2024

Inclusion Terms

• Malignant neoplasm of fourth cerebral ventricle
• Infratentorial malignant neoplasm NOS

U.S. Hospital Utilization

• An estimated 2,370 U.S. inpatient stays in 2023 included C71.7 among the documented diagnoses.
• 1,315 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)