2026 ICD-10-CM Diagnosis Code M63.80Disorders of muscle in diseases classified elsewhere, unspecified site

ICD-10-CM Codes›M00–M99›M60-M63›M63

ICD-10-CM M63.80
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M63.80 is a billable ICD-10-CM diagnosis code for disorders of muscle in diseases classified elsewhere, unspecified site. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 557 through 558. The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as cestode myositis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Muscle disorders.

Code Identity

ICD-10-CM Code
M63.80
Billable Status
Yes — Valid for Submission
Code Describes
Disorders of muscle in diseases classified elsewhere, unspecified site
Short Description
Disorders of muscle in diseases classd elswhr, unsp site
Parent Code
M63.8
Disorders of muscle in diseases classified elsewhere

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM60-M63Disorders of muscles
CategoryM63Disorders of muscle in diseases classified elsewhere
This CodeM63.80Disorders of muscle in diseases classified elsewhere, unspecified site

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M63.80.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cestode myositis
  • Congenital generalized lipodystrophy
  • Generalized congenital lipodystrophy with myopathy
  • Parasitic myositis

Clinical ClassificationClinical

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

CCSR MUS026
Muscle disorders
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Muscle Disorders

Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even paralysis.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M63.80 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
728.9 Muscle/ligament dis NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M63.80Overview

Is M63.80 (Disorders of muscle in diseases classified elsewhere) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report disorders of muscle in diseases classified elsewhere, unspecified site on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M63.80 group to?

On inpatient claims, disorders of muscle in diseases classified elsewhere, unspecified site maps to MS-DRG 557, 558, with relative weights from 0.8932 to 1.4869 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M63.80 be a principal diagnosis?

No. This is a manifestation code: disorders of muscle in diseases classified elsewhere, unspecified site describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

What is the ICD-9 equivalent of M63.80?

Under the General Equivalence Mappings, disorders of muscle in diseases classified elsewhere, unspecified site converts to ICD-9-CM 728.9 (muscle/ligament dis NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.