2026 ICD-10-CM Diagnosis Code D33.1Benign neoplasm of brain, infratentorial

ICD-10-CM Codes›C00–D49›D10-D36›D33

ICD-10-CM D33.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D33.1 is a billable ICD-10-CM diagnosis code for benign neoplasm of brain, infratentorial. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as benign neoplasm of brain stem. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Benign neoplasms.

Code Identity

ICD-10-CM Code
D33.1
Billable Status
Yes — Valid for Submission
Code Describes
Benign neoplasm of brain, infratentorial
Short Description
Benign neoplasm of brain, infratentorial
Same as the full description in the CMS dataset.
Parent Code
D33
Benign neoplasm of brain and other parts of central nervous system

Code Classification

ChapterC00–D49Neoplasms
SectionD10-D36Benign neoplasms, except benign neuroendocrine tumors
CategoryD33Benign neoplasm of brain and other parts of central nervous system
This CodeD33.1Benign neoplasm of brain, infratentorial

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Benign neoplasm of brain stem
  • Benign neoplasm of cerebellum
  • Benign neoplasm of infratentorial brain
  • Benign neoplasm of medulla oblongata
  • Benign neoplasm of pons
  • Benign neoplasm of spinal extradural space
  • Cerebellopontine angle meningioma
  • Cerebellopontine angle tumor
  • Neoplasm of extradural space

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Benign neoplasm of brain stem
  • Benign neoplasm of cerebellum
  • Benign neoplasm of fourth ventricle

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Papilloma
      • choroid plexus (lateral ventricle) (third ventricle)
        • fourth ventricle

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO073
Benign neoplasms
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
basis pedunculiC71.7C79.31–D33.1D43.1D49.6
brain NEC › cerebellopontine angleC71.6C79.31–D33.1D43.1D49.6
brain NEC › cerebellum NOSC71.6C79.31–D33.1D43.1D49.6
brain NEC › choroid plexusC71.7C79.31–D33.1D43.1D49.6
brain NEC › medulla oblongataC71.7C79.31–D33.1D43.1D49.6
brain NEC › midbrainC71.7C79.31–D33.1D43.1D49.6
brain NEC › peduncleC71.7C79.31–D33.1D43.1D49.6
brain NEC › ponsC71.7C79.31–D33.1D43.1D49.6
brain NEC › stemC71.7C79.31–D33.1D43.1D49.6
brain NEC › ventricle (floor) › fourthC71.7C79.31–D33.1D43.1D49.6
cerebellopontine (angle)C71.6C79.31–D33.1D43.1D49.6
cerebellum, cerebellarC71.6C79.31–D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) › peduncleC71.7C79.31–D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) › ventricle › fourthC71.7C79.31–D33.1D43.1D49.6
ependyma (brain) › fourth ventricleC71.7C79.31–D33.1D43.1D49.6
medulla › oblongataC71.7C79.31–D33.1D43.1D49.6
midbrainC71.7C79.31–D33.1D43.1D49.6
olive (brain)C71.7C79.31–D33.1D43.1D49.6
peduncle, cerebralC71.7C79.31–D33.1D43.1D49.6
pons (varolii)C71.7C79.31–D33.1D43.1D49.6
pyramid (brain)C71.7C79.31–D33.1D43.1D49.6
spine, spinal (column) › bulbC71.7C79.31–D33.1D43.1D49.6
stem, brainC71.7C79.31–D33.1D43.1D49.6
ventricle (cerebral) (floor) (lateral) (third) › fourthC71.7C79.31–D33.1D43.1D49.6
vermis, cerebellumC71.6C79.31–D33.1D43.1D49.6

Patient EducationClinical

Benign Tumors

Tumors are abnormal growths in your body. They can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D33.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
225.0 Benign neoplasm brain
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D33.1Overview

Is D33.1 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report benign neoplasm of brain, infratentorial on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of D33.1?

Under the General Equivalence Mappings, benign neoplasm of brain, infratentorial converts to ICD-9-CM 225.0 (benign neoplasm brain). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.