Q04

Non-Billable
ChapterQ00–Q99
Rankcategory
Official Description

Other congenital malformations of brain

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99).

CH17 Parent Instructions

Excludes2(Not included here)
  • inborn errors of metabolism (E70-E88)

Instructional Notes

Excludes1(Not coded here)

Clinical Hierarchy

CH17Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)
Q00-Q07Congenital malformations of the nervous system (Q00-Q07)
Q04Other congenital malformations of brain
Q04.0Congenital malformations of corpus callosum
Q04.1Arhinencephaly
Q04.2Holoprosencephaly
Q04.3Other reduction deformities of brain
Q04.4Septo-optic dysplasia of brain
Q04.5Megalencephaly
Q04.6Congenital cerebral cysts
Q04.8Other specified congenital malformations of brain
Q04.9Congenital malformation of brain, unspecified

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to Q04:

chapterCH17
Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to Q04. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

25 raw paths
Absence (of) (organ or part) (complete or partial)3 unique routes
brain
part of→Q04
cerebellum (vermis)→Q04
corpus callosum→Q04
Agenesis4 unique routes
brain
part of→Q04
cerebellum→Q04
corpus callosum→Q04
vermis of cerebellum→Q04
Agyria1 unique routes
Direct index entry→Q04
Anomaly, anomalous (congenital) (unspecified type)4 unique routes
brain (multiple)→Q04
cerebral→Q04
dura (brain)→Q04
meninges
cerebral→Q04
Aplasia3 unique routes
brain
part of→Q04
cerebellum→Q04
corpus callosum→Q04
Arhinencephaly1 unique routes
Direct index entry→Q04
Arnold-Chiari disease, obstruction or syndrome (type II)1 unique routes
type IV→Q04
Cyclencephaly1 unique routes
Direct index entry→Q04
Cyst (colloid) (mucous) (simple) (retention)6 unique routes
arachnoid, brain (acquired)
congenital→Q04
brain (acquired)(2 variants)
congenital→Q04
third ventricle (colloid), congenital→Q04
choroid plexus
congenital→Q04
paraphysis, cerebri, congenital→Q04
porencephalic→Q04
Deformity1 unique routes
brain (congenital)→Q04

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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