2026 ICD-10-CM Diagnosis Code M12.28Villonodular synovitis (pigmented), other specified site
ICD-10-CM Codes›M00–M99›M05-M14›M12
- Billable — Valid for Submission
- Not Chronic
M12.28 is a billable ICD-10-CM diagnosis code for villonodular synovitis (pigmented), other specified site. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 553 through 554. Coders also document this condition as diffuse tenosynovial giant cell tumor of shoulder region. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Diffuse tenosynovial giant cell tumor of shoulder region
- Diffuse tenosynovial giant cell tumor of sternoclavicular joint
- Diffuse tenosynovial giant cell tumor of tibiofibular joint
- Neoplasm of uncertain behavior of chest wall
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Villonodular synovitis (pigmented), vertebrae
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Synovitis - See Also: Tenosynovitis; - M65.90
- villonodular (pigmented) - M12.2
- specified joint NEC - M12.28
- vertebrae - M12.28
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Synovitis
- villonodular (pigmented)
- specified joint NEC
- Synovitis
- villonodular (pigmented)
- vertebrae
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Joint Disorders
Your joints are places where two or more bones come together. Your shoulders, elbows, hips, knees, and knuckles are all joints. Your spine has joints, too.
The full article covers:
- What are joints?
- What are joint disorders?
- What diseases can affect the joints?
- What types of joint disorders happen from sudden injuries?
- What types of joint disorders happen from overuse?
- How can I keep my joints healthy?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M12.28 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M12.28Overview
Is M12.28 (Villonodular synovitis (pigmented)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report villonodular synovitis (pigmented), other specified site on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M12.28 group to?
When villonodular synovitis (pigmented), other specified site is the principal diagnosis on an inpatient stay, it groups to MS-DRG 553, 554, with relative weights from 0.8301 to 1.2963 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M12.28?
Under the General Equivalence Mappings, villonodular synovitis (pigmented), other specified site converts to ICD-9-CM 719.28 (villonod synovit-jt NEC). The mapping is a direct match.
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.
