ICD-10-CM 2027
ICD-10 code for Porencephalic cyst
From the official ICD-10-CM alphabetic index entry “Cyst (colloid) (mucous) (simple) (retention) › porencephalic”. Page updated September 29, 2026.
About coding Porencephalic cyst
The ICD-10-CM code for Porencephalic cyst is Q04.6 (Congenital cerebral cysts). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on Q04.6.
Within Q04 (other congenital malformations of brain), Q04.6 is specifically for congenital cerebral cysts. Related codes cover congenital malformations of corpus callosum (Q04.0), Arhinencephaly (Q04.1), holoprosencephaly (Q04.2), other reduction deformities of brain (Q04.3), Septo-optic dysplasia of brain (Q04.4), Megalencephaly (Q04.5), other specified congenital malformations of brain (Q04.8) and congenital malformation of brain, unspecified (Q04.9).
Don't report Q04.6 together with the conditions in its Excludes1 note: acquired porencephalic cyst (G93.0).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
More specific Porencephalic cyst codes (official index)
- acquired G93.0 — Cerebral cysts
Don't confuse with (Excludes1 for Q04.6)
- acquired porencephalic cyst (G93.0)
Common questions about Porencephalic cyst ICD-10 codes
What is the ICD-10 code for Porencephalic cyst?
- Q04.6 — Congenital cerebral cysts. More specific codes apply when the documentation supports them: G93.0.
What is the ICD-10 code for acquired porencephalic cyst?
- G93.0 — Cerebral cysts.
Is Q04.6 billable?
- Yes. Q04.6 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q04.6 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q04.6 as a principal diagnosis.
Is Q04.6 a CC or MCC?
- Q04.6 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.