2027 ICD-10-CM Diagnosis Code M84.564APathological fracture in neoplastic disease, left fibula, initial encounter for fracture

ICD-10-CM Codes›M00–M99›M80-M85›M84

ICD-10-CM M84.564A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M84.564A is a billable ICD-10-CM diagnosis code for pathological fracture in neoplastic disease, left fibula, initial encounter for fracture. The 7th character A means initial encounter for fracture, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 542 through 544, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 214 closely related codes. 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.

M84.564A does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 87 for payment year 2027.

Code Identity

ICD-10-CM Code
M84.564A
Billable Status
Yes — Valid for Submission
Code Describes
Pathological fracture in neoplastic disease, left fibula, initial encounter for fracture
Short Description
Path fracture in neoplastic disease, left fibula, init
Parent Code
M84.564
Pathological fracture in neoplastic disease, left fibula

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM80-M85Disorders of bone density and structure
CategoryM84Disorder of continuity of bone
This CodeM84.564APathological fracture in neoplastic disease, left fibula, initial encounter for fracture

Medicare Risk Adjustment (HCC)Billing

M84.564A does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 87 — Osteoporosis, Vertebral and Pathological Fractures
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M84.564A: its own notes plus those printed at M84.5, M84, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

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 M84 Disorder of continuity of bone applies to 928 codes
  • traumatic fracture of bone-see fracture, by site
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)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From M84.5 Pathological fracture in neoplastic disease applies to 192 codes
  • underlying neoplasm

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

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From M84.5 Pathological fracture in neoplastic disease applies to 192 codes
  • The appropriate 7th character is to be added to each code from subcategory M84.5:
Values for category M84.5 Pathological Fracture Encounter
  • Ainitial encounter for fracture this code
  • Dsubsequent encounter for fracture with routine healing
  • Gsubsequent encounter for fracture with delayed healing
  • Ksubsequent encounter for fracture with nonunion
  • Psubsequent encounter for fracture with malunion
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M84.564A, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming M84.564A: they are not reported together with it, unless the two conditions are unrelated.

  • M84.4 Pathological fracture, not elsewhere classified
    pathological fracture in neoplastic disease (M84.5-) names M84.5-, which includes this code

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

Fractures

A fracture is a break in a bone. Fractures are usually caused by injuries. Since they can sometimes be serious, it's important to get medical care right away if you think you have a fracture.

The full article covers:

  • What is a fracture?
  • What are the different types of fractures?
  • What causes fractures?
  • What are the symptoms of a fracture?
  • How are fractures diagnosed?
  • What are the treatments for fractures?
  • Can fractures be prevented?

Read the full article at MedlinePlus

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

Convert M84.564A 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M84.564AOverview

Is M84.564A (Pathological fracture in neoplastic disease, left fibula) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pathological fracture in neoplastic disease, left fibula, initial encounter for fracture on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in M84.564A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for pathological fracture in neoplastic disease, left fibula, such as an emergency visit or first evaluation. In this category the CMS Tabular List defines A as "initial encounter for fracture".

What MS-DRG does M84.564A group to?

When pathological fracture in neoplastic disease, left fibula, initial encounter for fracture is the principal diagnosis on an inpatient stay, it groups to MS-DRG 543, 793, 791, 544, 542, with relative weights from 0.7404 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.

Is M84.564A a CC or MCC?

CMS lists M84.564A as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 214 closely related codes in its exclusion list.

What is the ICD-9 equivalent of M84.564A?

Under the General Equivalence Mappings, pathological fracture in neoplastic disease, left fibula, 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.

Does M84.564A risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: M84.564A maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 87 (Osteoporosis, Vertebral and Pathological Fractures).