2026 ICD-10-CM Diagnosis Code M84.573APathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture

ICD-10-CM Codes›M00–M99›M80-M85›M84

ICD-10-CM M84.573A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M84.573A is a billable ICD-10-CM diagnosis code for pathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 542 through 544. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as pathologic fracture of ankle at site of neoplasm. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Conditions due to neoplasm or the treatment of neoplasm; and Pathological fracture, initial encounter.

Code Identity

ICD-10-CM Code
M84.573A
Billable Status
Yes — Valid for Submission
Code Describes
Pathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture
Short Description
Path fracture in neoplastic disease, unsp ankle, init
Parent Code
M84.573
Pathological fracture in neoplastic disease, unspecified ankle

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM80-M85Disorders of bone density and structure
CategoryM84Disorder of continuity of bone
This CodeM84.573APathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M84.573A.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Pathologic fracture of ankle at site of neoplasm
  • Pathological fracture of ankle

Clinical ClassificationClinical

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

CCSR NEO074
Conditions due to neoplasm or the treatment of neoplasm
Default principal diagnosis: inpatient No · outpatient No
CCSR MUS014
Pathological fracture, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Ankle Injuries and Disorders

Your ankle bone and the ends of your two lower leg bones make up the ankle joint. Your ligaments, which connect bones to one another, stabilize and support it. Your muscles and tendons move it.

Read the full article at MedlinePlus

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

Convert M84.573A to ICD-9-CMHistory

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

ICD-9-CM
733.16 Path fx tibia fibula
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 M84.573AOverview

Is M84.573A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in M84.573A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for pathological fracture in neoplastic disease, unspecified ankle, such as an emergency visit or first evaluation.

What MS-DRG does M84.573A group to?

When pathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture is the principal diagnosis on an inpatient stay, it groups to MS-DRG 542, 543, 544, with relative weights from 0.7546 to 1.7665 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M84.573A?

Under the General Equivalence Mappings, pathological fracture in neoplastic disease, unspecified ankle, initial encounter for fracture converts to ICD-9-CM 733.16 (path fx tibia fibula). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.