2027 ICD-10-CM Diagnosis Code M79.659Pain in unspecified thigh

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.659
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M79.659 is a billable ICD-10-CM diagnosis code for pain in unspecified thigh. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 555 through 556. Coders also document this condition as lateral femoral cutaneous neuralgia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal pain, not low back pain.

This medical diagnosis code is frequently used in Family Practice, Internal Medicine, and Pediatrics medical specialties to designate conditions such pain in limb.

Code Identity

ICD-10-CM Code
M79.659
Billable Status
Yes — Valid for Submission
Code Describes
Pain in unspecified thigh
Short Description
Pain in unspecified thigh
Same as the full description in the CMS dataset.
Parent Code
M79.65
Pain in thigh

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM79Other and unspecified soft tissue disorders, not elsewhere classified
This CodeM79.659Pain in unspecified thigh

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Lateral femoral cutaneous neuralgia
  • Pain in femur
  • Thigh pain

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M79.659: its own notes plus those printed at M79.6, M79, 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 M79 Other and unspecified soft tissue disorders, not elsewhere classified applies to 52 codes
  • psychogenic rheumatism (F45.8)
  • soft tissue pain, psychogenic (F45.41)

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 M79.6 Pain in limb, hand, foot, fingers and toes applies to 31 codes
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.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M79.659, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming M79.659: they are not reported together with it, unless the two conditions are unrelated.

  • R52 Pain, unspecified
    limb pain (M79.6-) names M79.6-, which includes this code

Excludes2 3

These codes carry an Excludes2 note naming M79.659: its condition is not part of those codes, and both may be reported when the patient has both.

  • G89 Pain, not elsewhere classified
    limb pain (M79.6-) names M79.6-, which includes this code
  • M25.5 Pain in joint
    pain in limb (M79.6-) names M79.6-, which includes this code
  • R29.89 Other symptoms and signs involving the musculoskeletal system
    pain in limb (M79.6-) names M79.6-, which includes this code

Clinical ClassificationClinical

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

CCSR MUS010
Musculoskeletal pain, not low back pain
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 M79.659 to ICD-9-CMHistory

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

ICD-9-CM
729.5 Pain in limb
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 M79.659Overview

What is the ICD-10 code for pain in unspecified thigh?

The ICD-10-CM code for pain in unspecified thigh is M79.659 (sometimes written as M79659). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M79.659 (Pain in thigh) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pain in unspecified thigh on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M79.659 group to?

When pain in unspecified thigh is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8210 to 1.2908 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M79.659 be reported with F45.8?

Not as a rule. The Excludes1 note at M79, which applies to M79.659, lists "psychogenic rheumatism (F45.8)". 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 M79.659?

Under the General Equivalence Mappings, pain in unspecified thigh converts to ICD-9-CM 729.5 (pain in limb). The mapping is approximate, so confirm the match fits the documentation.