2024 ICD-10-CM Diagnosis Code M60.9

Myositis, unspecified

ICD-10-CM Code:
ICD-10 Code for:
Myositis, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Diseases of the musculoskeletal system and connective tissue

M60.9 is a billable diagnosis code used to specify a medical diagnosis of myositis, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like M60.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Maxillary myositis
  • Myositis
  • Myositis of left foot
  • Myositis of left lower leg
  • Myositis of left thigh
  • Myositis of right foot
  • Myositis of right lower leg
  • Myositis of right thigh

Clinical Classification

Clinical Information

  • Dermatomyositis

    a subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. the illness occurs with approximately equal frequency in children and adults. the skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. the disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. the childhood form of this disease tends to evolve into a systemic vasculitis. dermatomyositis may occur in association with malignant neoplasms. (from adams et al., principles of neurology, 6th ed, pp1405-6)
  • Myositis

    inflammation of a muscle or muscle tissue.
  • Myositis Ossificans

    a disease characterized by bony deposits or the ossification of muscle tissue.
  • Myositis, Inclusion Body

    progressive myopathies characterized by the presence of inclusion bodies on muscle biopsy. sporadic and hereditary forms have been described. the sporadic form is an acquired, adult-onset inflammatory vacuolar myopathy affecting proximal and distal muscles. familial forms usually begin in childhood and lack inflammatory changes. both forms feature intracytoplasmic and intranuclear inclusions in muscle tissue. (adams et al., principles of neurology, 6th ed, pp1409-10)
  • Nervous System Autoimmune Disease, Experimental

    experimental animal models for human autoimmune diseases of the nervous system. they include guillain-barre syndrome (see neuritis, autoimmune, experimental); myasthenia gravis (see myasthenia gravis, autoimmune, experimental); and multiple sclerosis (see encephalomyelitis, autoimmune, experimental).
  • Orbital Myositis

    inflammation of the extraocular muscle of the eye. it is characterized by swelling which can lead to ischemia, fibrosis, or orbital pseudotumor.
  • Polymyositis

    diseases characterized by inflammation involving multiple muscles. this may occur as an acute or chronic condition associated with medication toxicity (drug toxicity); connective tissue diseases; infections; malignant neoplasms; and other disorders. the term polymyositis is frequently used to refer to a specific clinical entity characterized by subacute or slowly progressing symmetrical weakness primarily affecting the proximal limb and trunk muscles. the illness may occur at any age, but is most frequent in the fourth to sixth decade of life. weakness of pharyngeal and laryngeal muscles, interstitial lung disease, and inflammation of the myocardium may also occur. muscle biopsy reveals widespread destruction of segments of muscle fibers and an inflammatory cellular response. (adams et al., principles of neurology, 6th ed, pp1404-9)
  • Pyomyositis

    an intramuscular suppuration of the large skeletal muscle groups. it is associated with infection such as staphylococcus aureus and pyoderma. it was known as a tropical disease but is increasing among the immunocompromised (immunocompromised host). symptoms include muscle pain, fever, and leucocytosis. it has been diagnosed by mri scans.
  • Orbital Pseudotumor

    a nonspecific tumor-like inflammatory lesion in the orbit of the eye. it is usually composed of mature lymphocytes; plasma cells; macrophages; leukocytes with varying degrees of fibrosis. orbital pseudotumors are often associated with inflammation of the extraocular muscles (orbital myositis) or inflammation of the lacrimal glands (dacryoadenitis).
  • Adult Dermatomyositis

    dermatomyositis in an adult.
  • Childhood Dermatomyositis|JDM|JDM|Juvenile Dermatomyositis|Juvenile Dermatomyositis

    an inflammatory myopathy of childhood resulting in muscle weakness, and associated with a characteristic skin rash.
  • Childhood Myositis Assessment Scale|CMAS|CMAS

    an observational performance-based instrument developed to evaluate muscle strength, physical function, and endurance in children with juvenile idiopathic inflammatory myopathy.
  • Cutaneous Dermatomyositis Disease Area and Severity Index|CDASI|CDASI

    an instrument that measures activity and damage in the skin of dermatomyositis patients.
  • Dermatomyositis

    inflammation of the skin and muscle.
  • Dermatomyositis Skin Severity Index|DSSI|DSSI

    an assessment of disease activity in the skin of patients with dermatomyositis.
  • Dermatopolymyositis in Neoplastic Disease|Dermato(poly)myositis in neoplastic disease

    evidence of dermatopolymyositis in neoplastic disease.
  • Dermatopolymyositis, Unspecified with Myopathy|Dermatopolymyositis, unspecified with myopathy

    evidence of dermatopolymyositis, unspecified with myopathy.
  • Dermatopolymyositis, Unspecified with Other Organ Involvement|Dermatopolymyositis, unspecified with other organ involvement

    evidence of dermatopolymyositis, unspecified with other organ involvement.
  • Dermatopolymyositis, Unspecified with Respiratory Involvement|Dermatopolymyositis, unspecified with respiratory involvement

    evidence of dermatopolymyositis, unspecified with respiratory involvement.
  • Dermatopolymyositis, Unspecified without Myopathy|Dermatopolymyositis, unspecified without myopathy

    evidence of dermatopolymyositis, unspecified without myopathy.
  • Dermatopolymyositis, Unspecified, Organ Involvement Unspecified|Dermatopolymyositis, unspecified, organ involvement unspecified

    evidence of dermatopolymyositis, unspecified, organ involvement unspecified.
  • EXOSC10 wt Allele|Exosome Component 10 wt Allele|PM-Scl|PM/Scl-100|PMSCL|PMSCL Autoantigen, 100-kD Gene|PMSCL2|Polymyositis/Scleroderma Autoantigen 2 (100kD) Gene|Polymyositis/Scleroderma Autoantigen 2, 100kDa Gene|Polymyositis/Scleroderma Autoantigen, 100-kD Gene|RRP6|Rrp6p|p2|p3|p4

    human exosc10 wild-type allele is located in the vicinity of 1p36.22 and is approximately 33 kb in length. this allele, which encodes exosome component 10 protein, is involved in rna maturation and degradation of rna processing by-products.
  • Exosome Component 10|Autoantigen PM-SCL|Autoantigen PM/Scl|EC 3.1.13.-|EXOSC10|P100 Polymyositis-Scleroderma Overlap Syndrome-Associated Autoantigen|PM/Scl-100|Polymyositis/Scleroderma Autoantigen 100 kDa|Polymyositis/Scleroderma Autoantigen 2

    exosome component 10 (885 aa, ~101 kda) is encoded by the human exosc10 gene. this protein plays a role in the maturation and degradation of rna.
  • Fibrodysplasia Ossificans Progressiva|Myositis Ossificans Progressiva

    a condition in which there is progressive heterotopic bone formation of the tendons and muscles.
  • Fibromyositis

    inflammation and fibrous degeneration of a muscle.
  • Grade 1 Myositis, CTCAE|CTCAE Grade 1 Myositis (inflammation/damage of muscle)|Grade 1 Myositis|Grade 1 Myositis (inflammation/damage of muscle)

    mild pain
  • Grade 2 Infective Myositis, CTCAE|Grade 2 Infective myositis

    localized; local intervention indicated (e.g., topical antibiotic, antifungal, or antiviral)
  • Grade 2 Myositis, CTCAE|CTCAE Grade 2 Myositis (inflammation/damage of muscle)|Grade 2 Myositis|Grade 2 Myositis (inflammation/damage of muscle)

    moderate pain associated with weakness; pain limiting instrumental adl
  • Grade 3 Infective Myositis, CTCAE|Grade 3 Infective myositis

    iv antibiotic, antifungal, or antiviral intervention indicated; invasive intervention indicated
  • Grade 3 Myositis, CTCAE|CTCAE Grade 3 Myositis (inflammation/damage of muscle)|Grade 3 Myositis|Grade 3 Myositis (inflammation/damage of muscle)

    pain associated with severe weakness; limiting self care adl
  • Grade 4 Infective Myositis, CTCAE|Grade 4 Infective myositis

    life-threatening consequences; urgent intervention indicated
  • Grade 4 Myositis, CTCAE|CTCAE Grade 4 Myositis (inflammation/damage of muscle)|Grade 4 Myositis|Grade 4 Myositis (inflammation/damage of muscle)

    life-threatening consequences; urgent intervention indicated
  • Grade 5 Infective Myositis, CTCAE|Grade 5 Infective myositis

  • Inclusion Body Myositis

    an acquired or hereditary chronic inflammatory disorder of the muscles characterized by the morphologic finding of vacuoles and filamentous inclusions in the muscle tissues.
  • Infectious Myositis|Infective Myositis|Infective myositis

    an infectious process affecting the skeletal muscles. it can be caused by viruses (including hiv), bacteria, fungi, and parasites. symptoms include muscle weakness and muscle pain.
  • Infective Myositis, CTCAE|Infective Myositis|Infective myositis

    a disorder characterized by an infectious process involving the skeletal muscles.
  • Interferon-Induced Helicase C Domain-Containing Protein 1|CADM-140 Autoantigen|Clinically Amyopathic Dermatomyositis Autoantigen 140 kDa|EC|Helicard|Helicase with 2 CARD Domains|IFIH1|Interferon-Induced With Helicase C Domain Protein 1|MDA-5|Melanoma Differentiation Associated Protein-5|Melanoma Differentiation-Associated Protein 5|Murabutide Down-Regulated Protein|RLR-2|RNA Helicase-DEAD Box Protein 116

    interferon-induced helicase c domain-containing protein 1 (1025 aa, ~117 kda) is encoded by the human ifih1 gene. this protein is involved in the positive regulation of antiviral responses.
  • International Myositis Assessment and Clinical Studies Group|IMACS|IMACS

    a coalition of health care providers and researchers with experience and interest in the myositis syndromes. (adapted from niehs website)
  • Interstitial Myositis

    a form of myositis that is characterized by the formation of connective tissue within the muscle.
  • Juvenile Dermatomyositis Sine Myositis|Juvenile Amyopathic Dermatomyositis|Juvenile Amyopathic Dermatomyositis|Juvenile Dermatomyositis sine Myositis|Juvenile dermatomyositis without myopathy

    a rare form of juvenile dermatomyositis that manifests with characteristic cutaneous findings for at least six months in the absence of any detectable muscle involvement.
  • Juvenile Dermatomyositis with Myopathy|Juvenile dermatomyositis with myopathy

    evidence of juvenile dermatomyositis with myopathy.
  • Juvenile Dermatomyositis with Other Organ Involvement|Juvenile dermatomyositis with other organ involvement

    evidence of juvenile dermatomyositis with other organ involvement.
  • Juvenile Dermatomyositis with Respiratory Involvement|Juvenile dermatomyositis with respiratory involvement

    evidence of juvenile dermatomyositis with respiratory involvement.
  • Juvenile Dermatomyositis, Organ Involvement Unspecified|Juvenile dermatomyositis, organ involvement unspecified

    evidence of juvenile dermatomyositis, organ involvement unspecified.
  • Juvenile Polymyositis|JPM

    an idiopathic inflammatory myopathy of childhood resulting in muscle weakness.
  • Musculoskeletal Chest Pain due to Myositis|Musculoskeletal chest pain due to myositis

    a condition in which there is musculoskeletal chest pain secondary to inflammation of the muscle tissue. (acc/aha)
  • Myositis

    an inflammatory process affecting the skeletal muscles. causes include infections, injuries, and autoimmune disorders.
  • Myositis Activities Profile|MAP|MAP

    an assessment of disease-specific limitations of activities of daily living in patients with polymyositis and dermatomyositis.
  • Myositis Damage Index|MDI|MDI

    a scoring system used to measure damage from myositis, complications of therapy, or other events.
  • Myositis Disease Activity Assessment Tool|MDAAT|MDAAT

    a tool that assesses disease activity of extramuscular organ systems and muscle to assess patients with adult and juvenile dermatomyositis, polymyositis, and inclusion body myositis.
  • Myositis Ossificans

    a self-limited benign neoplasm characterized by a zonal architecture. it is composed of spindle cells oriented randomly or in short intersecting fascicles. peripherally, the spindle cells merge with osteoblasts that rim and populate ill-defined trabeculae and sheets of unmineralized woven bone, which is surrounded by well-formed trabecular and cortical-type bone that remodels into lamellar bone. treatment is usually simple excision. prognosis is excellent; recurrence is uncommon. (who 2020)
  • Myositis, CTCAE 5.0|Myositis|Myositis

    a disorder characterized by inflammation involving the skeletal muscles.
  • Orbital Myositis

    a rare form of myositis that affects only the orbital muscles.
  • Other Dermatomyositis with Myopathy|Other dermatomyositis with myopathy

    evidence of other dermatomyositis with myopathy not specified elsewhere.
  • Other Dermatomyositis with Other Organ Involvement|Other dermatomyositis with other organ involvement

    evidence of other dermatomyositis with other organ involvement not specified elsewhere.
  • Other Dermatomyositis with Respiratory Involvement|Other dermatomyositis with respiratory involvement

    evidence of other dermatomyositis with respiratory involvement not specified elsewhere.
  • Other Dermatomyositis without Myopathy|Other dermatomyositis without myopathy

    evidence of other dermatomyositis without myopathy not specified elsewhere.
  • Other Dermatomyositis, Organ Involvement Unspecified|Other dermatomyositis, organ involvement unspecified

    evidence of other dermatomyositis, organ involvement unspecified not specified elsewhere.
  • P100 Polymyositis-scleroderma Autoantigen Antibody Measurement|Exosome Component 10 Antibody Measurement|P100 Polymyositis-scleroderma Autoag Ab|P100 Polymyositis-scleroderma Autoag Ab|PSP100AB

    the determination of the p100 polymyositis-scleroderma autoantigen antibody present in a sample.
  • Polymyositis with Myopathy|Polymyositis with myopathy

    evidence of polymyositis with myopathy.
  • Polymyositis with Other Organ Involvement|Polymyositis with other organ involvement

    evidence of polymyositis with other organ involvement.
  • Polymyositis with Respiratory Involvement|Polymyositis with respiratory involvement

    evidence of polymyositis with respiratory involvement.
  • Polymyositis|Polymyositis, organ involvement unspecified|polymyositis

    an idiopathic inflammatory disorder affecting the muscles. it presents with symmetrical proximal muscle weakness and elevated skeletal muscle enzymes.
  • Proliferative Myositis

    a rapidly growing, poorly circumscribed, mass-forming proliferation that arises from the skeletal muscle. it is characterized by the presence of spindle-shaped fibroblasts, round ganglion-like cells, myxoid to collagenous stroma formation, and high mitotic activity. it recurs only rarely following local excision and does not metastasize.
  • Pyomyositis|Tropical Pyomyositis

    a suppurative infection of muscle.
  • Scleroderma Polymyositis Overlap Syndrome|Scleroderma Polymyositis

    a rare autoimmune disorder in which patients present with overlapping symptoms of systemic scleroderma and polymyositis or dermatomyositis.
  • Traumatic Myositis Ossificans

    myositis ossificans resulting from trauma.

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Convert M60.9 to ICD-9-CM

  • ICD-9-CM Code: 729.1 - Myalgia and myositis NOS
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education


Myositis means inflammation of the muscles that you use to move your body. An injury, infection, or autoimmune disease can cause it. Two specific kinds are polymyositis and dermatomyositis. Polymyositis causes muscle weakness, usually in the muscles closest to the trunk of your body. Dermatomyositis causes muscle weakness, plus a skin rash.

Other symptoms of myositis may include:

  • Fatigue after walking or standing
  • Tripping or falling
  • Trouble swallowing or breathing

Doctors may use a physical exam, lab tests, imaging tests and a muscle biopsy to diagnose myositis. There is no cure for these diseases, but you can treat the symptoms. Polymyositis and dermatomyositis are first treated with high doses of a corticosteroid. Other options include medications, physical therapy, exercise, heat therapy, assistive devices, and rest.

NIH: National Institute of Neurological Disorders and Stroke

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.


[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.