2026 ICD-10-CM Diagnosis Code D43.1Neoplasm of uncertain behavior of brain, infratentorial

ICD-10-CM CodesC00–D49D37-D48D43

ICD-10-CM D43.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D43.1 is a billable ICD-10-CM diagnosis code for neoplasm of uncertain behavior of brain, infratentorial. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neoplasms of unspecified nature or uncertain behavior.

Code Identity

ICD-10-CM Code
D43.1
Billable Status
Yes — Valid for Submission
Code Describes
Neoplasm of uncertain behavior of brain, infratentorial
Short Description
Neoplasm of uncertain behavior of brain, infratentorial
Same as the full description in the CMS dataset.
Parent Code
Neoplasm of uncertain behavior of brain and central nervous system

Code Classification

ChapterC00–D49Neoplasms
SectionD37-D48Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes
CategoryD43Neoplasm of uncertain behavior of brain and central nervous system
This CodeD43.1Neoplasm of uncertain behavior of brain, infratentorial

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cerebellar hemangioblastoma
  • Cerebellar liponeurocytoma
  • Hemangioblastoma of brainstem
  • Hemangioblastoma of central nervous system
  • Low grade glioma of cerebellum
  • Neoplasm of uncertain behavior of brain stem
  • Neoplasm of uncertain behavior of cerebellum
  • Neoplasm of uncertain or unknown behavior of brain, infratentorial
  • Pilocytic astrocytoma
  • Pilocytic astrocytoma of cerebellum

Tabular List NotesGuidance

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

Inclusion Terms

  • Neoplasm of uncertain behavior of brain stem
  • Neoplasm of uncertain behavior of cerebellum
  • Neoplasm of uncertain behavior of fourth ventricle

Clinical ClassificationClinical

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

CCSR NEO072
Neoplasms of unspecified nature or uncertain behavior
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 pedunculiC71.7C79.31D33.1D43.1D49.6
brain NEC cerebellopontine angleC71.6C79.31D33.1D43.1D49.6
brain NEC cerebellum NOSC71.6C79.31D33.1D43.1D49.6
brain NEC choroid plexusC71.7C79.31D33.1D43.1D49.6
brain NEC medulla oblongataC71.7C79.31D33.1D43.1D49.6
brain NEC midbrainC71.7C79.31D33.1D43.1D49.6
brain NEC peduncleC71.7C79.31D33.1D43.1D49.6
brain NEC ponsC71.7C79.31D33.1D43.1D49.6
brain NEC stemC71.7C79.31D33.1D43.1D49.6
brain NEC ventricle (floor) fourthC71.7C79.31D33.1D43.1D49.6
cerebellopontine (angle)C71.6C79.31D33.1D43.1D49.6
cerebellum, cerebellarC71.6C79.31D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) peduncleC71.7C79.31D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) ventricle fourthC71.7C79.31D33.1D43.1D49.6
ependyma (brain) fourth ventricleC71.7C79.31D33.1D43.1D49.6
medulla oblongataC71.7C79.31D33.1D43.1D49.6
midbrainC71.7C79.31D33.1D43.1D49.6
olive (brain)C71.7C79.31D33.1D43.1D49.6
peduncle, cerebralC71.7C79.31D33.1D43.1D49.6
pons (varolii)C71.7C79.31D33.1D43.1D49.6
pyramid (brain)C71.7C79.31D33.1D43.1D49.6
spine, spinal (column) bulbC71.7C79.31D33.1D43.1D49.6
stem, brainC71.7C79.31D33.1D43.1D49.6
ventricle (cerebral) (floor) (lateral) (third) fourthC71.7C79.31D33.1D43.1D49.6
vermis, cerebellumC71.6C79.31D33.1D43.1D49.6

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

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

Convert D43.1 to ICD-9-CMHistory

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

ICD-9-CM
237.5 Unc beh neo brain/spinal
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 D43.1Overview

Is D43.1 a billable code?

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

What is the ICD-9 equivalent of D43.1?

Under the General Equivalence Mappings, neoplasm of uncertain behavior of brain, infratentorial converts to ICD-9-CM 237.5 (unc beh neo brain/spinal). 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.