2026 ICD-10-CM Diagnosis Code N65.1Disproportion of reconstructed breast

ICD-10-CM Codes›N00–N99›N60-N65›N65

ICD-10-CM N65.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N65.1 is a billable ICD-10-CM diagnosis code for disproportion of reconstructed breast. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 600 through 601. The code is restricted by the Medicare Code Editor to adult patients (age 15 through 124). Coders also document this condition as breasts asymmetrical. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nonmalignant breast conditions.

Code Identity

ICD-10-CM Code
N65.1
Billable Status
Yes — Valid for Submission
Code Describes
Disproportion of reconstructed breast
Short Description
Disproportion of reconstructed breast
Same as the full description in the CMS dataset.
Parent Code
N65
Deformity and disproportion of reconstructed breast

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN60-N65Disorders of breast
CategoryN65Deformity and disproportion of reconstructed breast
This CodeN65.1Disproportion of reconstructed breast

Code EditsBilling

Medicare Code Editor checks that affect claim validity for N65.1.

Adult diagnoses
The Medicare Code Editor detects inconsistencies in adult cases by checking a patient's age and any diagnosis on the patient's record. The adult code edits apply to patients age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Breasts asymmetrical
  • Disproportion of reconstructed breast
  • Disproportion of reconstructed left breast
  • Disproportion of reconstructed right breast
  • Symmetry of breasts - finding

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Breast asymmetry between native breast and reconstructed breast
  • Disproportion between native breast and reconstructed breast

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Asymmetry
      • between native and reconstructed breast
    • Complication(s) (from) (of)
      • reconstructed breast
        • asymmetry between native and reconstructed breast
    • Complication(s) (from) (of)
      • reconstructed breast
        • disproportion between native and reconstructed breast
    • Disproportion
      • between native and reconstructed breast

Clinical ClassificationClinical

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

CCSR GEN017
Nonmalignant breast conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Breast Diseases

Breast diseases include various conditions and changes in your breast. Most women experience breast changes at some time. Your age, hormone levels, and medicines you take may cause lumps, bumps, and discharges of fluids that are not breast milk.

The full article covers:

  • What are breast diseases?
  • What are the symptoms of breast disease?
  • How are breast diseases diagnosed?
  • What are the treatments for breast disease?

Read the full article at MedlinePlus

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

Convert N65.1 to ICD-9-CMHistory

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

ICD-9-CM
612.1 Disproportn reconst brst
Exact Match The mapping is direct, with no qualifiers.

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 N65.1Overview

Is N65.1 (Deformity and disproportion of reconstructed breast) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report disproportion of reconstructed breast on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N65.1 group to?

When disproportion of reconstructed breast is the principal diagnosis on an inpatient stay, it groups to MS-DRG 600, 601, with relative weights from 0.6050 to 1.0416 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can N65.1 be reported for?

The Medicare Code Editor checks disproportion of reconstructed breast against patient demographics: this code is intended for adult patients (age 15 through 124). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of N65.1?

Under the General Equivalence Mappings, disproportion of reconstructed breast converts to ICD-9-CM 612.1 (disproportn reconst brst). The mapping is a direct match.

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.