G73.1 Lambert-Eaton syndrome in neoplastic disease

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Excludes1 (never code together)

• Lambert-Eaton syndrome not associated with neoplasm (G70.80-G70.81)

Code first

• underlying neoplasm (C00-D49)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 196 — Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders
• CMS-HCC V22: HCC 75 — Myasthenia Gravis/Myoneural Disorders, Inflammatory and Toxic Neuropathy
• RxHCC V08: HCC 153 — Myasthenia Gravis and Other Myoneural Disorders
• ESRD V24: HCC 75

MS-DRG index

Defines the logic of DRG(s) 056-057 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 358.31 Lambert-Eaton syndrome in neoplastic disease

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.
• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to G73.1

Back-references to G73.1

• Type 1 Excludes: G70.81 Lambert-Eaton syndrome in disease classified elsewhere ("Lambert-Eaton syndrome in neoplastic disease (G73.1)")

Back-references to G73

• Code First: M62.84 Sarcopenia ("disorders of myoneural junction and muscle disease in diseases classified elsewhere (G73.-)")

Diagnosis Index entries for G73.1

• Syndrome › Lambert-Eaton › in › neoplastic disease

Nearby codes

• G73 Disorders of myoneural junction and muscle in diseases classified elsewhere
• G73.1 Lambert-Eaton syndrome in neoplastic disease (this code)
• G73.3 Myasthenic syndromes in other diseases classified elsewhere
• G73.7 Myopathy in diseases classified elsewhere