2026 ICD-10-CM Diagnosis Code Q04.6Congenital cerebral cysts

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q04

ICD-10-CM Q04.6
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q04.6 is a billable ICD-10-CM diagnosis code for congenital cerebral cysts. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

Code Identity

ICD-10-CM Code
Q04.6
Billable Status
Yes — Valid for Submission
Code Describes
Congenital cerebral cysts
Short Description
Congenital cerebral cysts
Same as the full description in the CMS dataset.
Parent Code
Q04
Other congenital malformations of brain

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ04Other congenital malformations of brain
This CodeQ04.6Congenital cerebral cysts

Present on Admission (POA)Billing

Q04.6 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Absent tibia, polydactyly, arachnoid cyst syndrome
  • Arachnoid cyst
  • Bilateral congenital cataract of eyes
  • Cerebellar ataxia, intellectual disability, oculomotor apraxia, cerebellar cysts syndrome
  • Cerebral arachnoid cyst
  • Choroid plexus cyst
  • Colloid brain cyst
  • Colloid cyst of third ventricle
  • Congenital choroid plexus cyst
  • Congenital cyst of brain
  • Congenital cyst of cerebrum
  • Congenital malformation of the meninges
  • Congenital porencephalic cyst
  • Congenital porencephaly
  • Congenital pseudoporencephaly
  • Multiple congenital cysts of brain
  • Multiple congenital cysts of cerebrum
  • Partial agenesis of corpus callosum
  • Partial corpus callosum agenesis, cerebellar vermis hypoplasia with posterior fossa cysts syndrome
  • Persistent Blake's pouch cyst
  • Porencephalic cyst
  • Porencephaly, cerebellar hypoplasia, internal malformations syndrome
  • Porencephaly, microcephaly, bilateral congenital cataract syndrome
  • Posterior fossa arachnoid cyst
  • Pseudoporencephaly
  • Schizencephaly
  • Single congenital cyst of brain
  • Single congenital cyst of cerebrum

Tabular List NotesGuidance

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

Inclusion Terms

  • Porencephaly
  • Schizencephaly

Type 1 Excludes

  • acquired porencephalic cyst G93.0

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.

    • Cyst(colloid) (mucous) (simple) (retention)
      • arachnoid, brain (acquired)
        • congenital
    • Cyst(colloid) (mucous) (simple) (retention)
      • brain (acquired)
        • congenital
    • Cyst(colloid) (mucous) (simple) (retention)
      • brain (acquired)
        • third ventricle (colloid), congenital
    • Cyst(colloid) (mucous) (simple) (retention)
      • choroid plexus
        • congenital
    • Cyst(colloid) (mucous) (simple) (retention)
      • paraphysis, cerebri, congenital
    • Cyst(colloid) (mucous) (simple) (retention)
      • porencephalic
    • Degeneration, degenerative
      • brain (cortical) (progressive)
        • cystic
          • congenital
    • Porencephaly(congenital) (developmental) (true)
    • Schizencephaly

Clinical ClassificationClinical

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

CCSR MAL004
Nervous system congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Schizencephaly

    cortical malformations characterized by grey matter-lined cleft or cyst that extends from the ependyma often to the pia mater outer surface. the grey matter that lines the cleft is often polymicrogyria. it is associated with developmental delay, motor disturbance and seizures.

  • Schizencephaly

    a rare developmental abnormality characterized by the presence of clefs in the cerebral hemispheres. the abnormality may involve one or both cerebral hemispheres. signs and symptoms include developmental delays, mental retardation, paralysis, presence of a small head, and seizures.

  • Porencephalic Cyst

    a congenital or acquired cystic cavity within the cerebral hemisphere.

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 Q04.6 to ICD-9-CMHistory

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

ICD-9-CM
742.4 Brain anomaly NEC
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 Q04.6Overview

Is Q04.6 (Other congenital malformations of brain) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital cerebral cysts on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is Q04.6 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital cerebral cysts on inpatient claims.

What is the ICD-9 equivalent of Q04.6?

Under the General Equivalence Mappings, congenital cerebral cysts converts to ICD-9-CM 742.4 (brain anomaly NEC). 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.