2027 ICD-10-CM Diagnosis Code M67.261Synovial hypertrophy, not elsewhere classified, right lower leg

ICD-10-CM Codes›M00–M99›M65-M67›M67

ICD-10-CM M67.261
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M67.261 is a billable ICD-10-CM diagnosis code for synovial hypertrophy, not elsewhere classified, right lower leg. 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 Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M67.261
Billable Status
Yes — Valid for Submission
Code Describes
Synovial hypertrophy, not elsewhere classified, right lower leg
Short Description
Synovial hypertrophy, NEC, right lower leg
Parent Code
M67.26
Synovial hypertrophy, not elsewhere classified, lower leg

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM67Other disorders of synovium and tendon
This CodeM67.261Synovial hypertrophy, not elsewhere classified, right lower leg

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M67.261: its own notes plus those printed at M67.2, M67, 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.

From M67.2 Synovial hypertrophy, not elsewhere classified applies to 24 codes
  • villonodular synovitis (pigmented) (M12.2-)
From M67 Other disorders of synovium and tendon applies to 143 codes
  • palmar fascial fibromatosis [Dupuytren] (M72.0)
  • tendinitis NOS (M77.9-)
  • xanthomatosis localized to tendons (E78.2)

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.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • 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.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • 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.

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

Patient EducationClinical

Leg Injuries and Disorders

Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).

Read the full article at MedlinePlus

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

Convert M67.261 to ICD-9-CMHistory

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

ICD-9-CM
727.89 Synov/tend/bursa dis NEC
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M67.261Overview

What is the ICD-10 code for synovial hypertrophy, not elsewhere classified, right lower leg?

The ICD-10-CM code for synovial hypertrophy, not elsewhere classified, right lower leg is M67.261 (sometimes written as M67261). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M67.261 (Synovial hypertrophy, not elsewhere classified, lower leg) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report synovial hypertrophy, not elsewhere classified, right lower leg on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M67.261 group to?

When synovial hypertrophy, not elsewhere classified, right lower leg 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 M67.261 be reported with a code from M12.2?

Not as a rule. The Excludes1 note at M67.2, which applies to M67.261, lists "villonodular synovitis (pigmented) (M12.2-)". 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 M67.261?

Under the General Equivalence Mappings, synovial hypertrophy, not elsewhere classified, right lower leg converts to ICD-9-CM 727.89 (synov/tend/bursa dis NEC). The mapping is approximate, so confirm the match fits the documentation.