G13.1 Other systemic atrophy primarily affecting central nervous system in neoplastic disease

Billable ICD-10-CM code, FY2026.

Applicable to

• Paraneoplastic limbic encephalopathy

Code first

• underlying neoplasm (C00-D49)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 75 — Myasthenia Gravis/Myoneural Disorders, Inflammatory and Toxic Neuropathy
• RxHCC V08: HCC 158 — Inflammatory and Toxic Neuropathy
• ESRD V24: HCC 75

MS-DRG index

Defines the logic of DRG(s) 073-074 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 357.3 Polyneuropathy in malignant disease (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Manifestation codes as principal diagnosis: Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and are not allowed as principal diagnosis.

Diagnosis Index entries for G13.1

• Atrophy, atrophic (of) › systemic affecting central nervous system › in › neoplastic disease
• Encephalopathy (acute) › in (due to) (with) › neoplastic disease (see also Neoplasm)

Nearby codes

• G13 Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere
• G13.0 Paraneoplastic neuromyopathy and neuropathy
• G13.1 Other systemic atrophy primarily affecting central nervous system in neoplastic disease (this code)
• G13.2 Systemic atrophy primarily affecting the central nervous system in myxedema
• G13.8 Systemic atrophy primarily affecting central nervous system in other diseases classified elsewhere