2026 ICD-10-CM Diagnosis Code M12.242Villonodular synovitis (pigmented), left hand

ICD-10-CM Codes›M00–M99›M05-M14›M12

ICD-10-CM M12.242
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M12.242 is a billable ICD-10-CM diagnosis code for villonodular synovitis (pigmented), left hand. 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 hand. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M12.242
Billable Status
Yes — Valid for Submission
Code Describes
Villonodular synovitis (pigmented), left hand
Short Description
Villonodular synovitis (pigmented), left hand
Same as the full description in the CMS dataset.
Parent Code
M12.24
Villonodular synovitis (pigmented), hand

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM05-M14Inflammatory polyarthropathies
CategoryM12Other and unspecified arthropathy
This CodeM12.242Villonodular synovitis (pigmented), left hand

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Diffuse tenosynovial giant cell tumor of hand
  • Diffuse tenosynovial giant cell tumor of left hand

Clinical ClassificationClinical

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

CCSR MUS009
Tendon and synovial disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Joint Disorders

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  • What diseases can affect the joints?
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  • What types of joint disorders happen from overuse?
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Read the full article at MedlinePlus

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

Convert M12.242 to ICD-9-CMHistory

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

ICD-9-CM
719.24 Villonod synovit-hand
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 M12.242Overview

Is M12.242 (Villonodular synovitis (pigmented), hand) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report villonodular synovitis (pigmented), left hand on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M12.242 group to?

When villonodular synovitis (pigmented), left hand 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 M12.242?

Under the General Equivalence Mappings, villonodular synovitis (pigmented), left hand converts to ICD-9-CM 719.24 (villonod synovit-hand). 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.