2027 ICD-10-CM Diagnosis Code M61.121Myositis ossificans progressiva, right upper arm
ICD-10-CM Codes›M00–M99›M60-M63›M61
- Billable — Valid for Submission
- Chronic Condition
M61.121 is a billable ICD-10-CM diagnosis code for myositis ossificans progressiva, right upper arm. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 557 through 558. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Muscle disorders.
Code Identity
Code Classification
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M61.121: its own notes plus those printed at block M60-M63 and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Fibrodysplasia Ossificans Progressiva
a condition in which there is progressive heterotopic bone formation of the tendons and muscles.
Patient EducationClinical
Bone Diseases
Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M61.121 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M61.121Overview
What is the ICD-10 code for myositis ossificans progressiva, right upper arm?
The ICD-10-CM code for myositis ossificans progressiva, right upper arm is M61.121 (sometimes written as M61121). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M61.121 (Myositis ossificans progressiva, upper arm) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report myositis ossificans progressiva, right upper arm on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M61.121 group to?
When myositis ossificans progressiva, right upper arm is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8873 to 1.4883 depending on complications. Higher weights mean higher Medicare reimbursement.
Can M61.121 be reported with a code from M33?
Not as a rule. The Excludes1 note at block M60-M63, which applies to M61.121, lists "dermatopolymyositis (M33.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of M61.121?
Under the General Equivalence Mappings, myositis ossificans progressiva, right upper arm converts to ICD-9-CM 728.11 (prog myositis ossificans). The mapping is approximate, so confirm the match fits the documentation.
