2026 ICD-10-CM Diagnosis Code G93.42Megalencephalic leukoencephalopathy with subcortical cysts

ICD-10-CM Codes›G00–G99›G89-G99›G93

ICD-10-CM G93.42
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G93.42 is a billable ICD-10-CM diagnosis code for megalencephalic leukoencephalopathy with subcortical cysts. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 974 through 976. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (often hereditary or degenerative).

Code Identity

ICD-10-CM Code
G93.42
Billable Status
Yes — Valid for Submission
Code Describes
Megalencephalic leukoencephalopathy with subcortical cysts
Short Description
Megalencephalic leukoencephalopathy with subcortical cysts
Same as the full description in the CMS dataset.
Parent Code
G93.4
Other and unspecified encephalopathy

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG89-G99Other disorders of the nervous system
CategoryG93Other disorders of brain
This CodeG93.42Megalencephalic leukoencephalopathy with subcortical cysts

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.

    • Leukoencephalopathy
      • megalencephalic, with subcortical cysts

Clinical ClassificationClinical

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

CCSR NVS006
Other nervous system disorders (often hereditary or degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement G93.42 replaces the following previously assigned code(s):

  • G93.49 - Other encephalopathy
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025RevisedCode revised
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G93.42Overview

Is G93.42 (Other and unspecified encephalopathy) a billable code?

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

What MS-DRG does G93.42 group to?

When megalencephalic leukoencephalopathy with subcortical cysts is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 975, 976, with relative weights from 0.8945 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

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.