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ICD-10-CM 2027 diagnosis code

N64.2Atrophy of breast

✓ Billable / specific

N64.2 is a valid, billable ICD-10-CM code for atrophy of breast. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Breast atrophy.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About N64.2

N64.2 is the ICD-10-CM diagnosis code for atrophy of breast. It belongs to category N64 (other disorders of breast), block N60-N65 (disorders of breast) and chapter 14 (diseases of the genitourinary system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within N64 (other disorders of breast), N64.2 is specifically for atrophy of breast. Related codes cover fissure and fistula of nipple (N64.0), fat necrosis of breast (N64.1), Galactorrhea not associated with childbirth (N64.3), Mastodynia (N64.4), other signs and symptoms in breast (N64.5), other specified disorders of breast (N64.8) and disorder of breast, unspecified (N64.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 600 (Non-Malignant Breast Disorders with CC/MCC, relative weight 0.9975) and DRG 601 (Non-Malignant Breast Disorders without CC/MCC, relative weight 0.6017), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 611.4 (atrophy of breast).

Notes that apply from higher levels

Instructions written at a parent level also apply to N64.2.

› From N64 Other disorders of breast
Excludes2
  • mechanical complication of breast prosthesis and implant (T85.4-)

Broader instructions also apply from N60-N65 Disorders of breast and Chapter 14: Diseases of the genitourinary system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to N64.2.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 09 · Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast

ICD-9-CM equivalent

Converter →
  • 611.4Atrophy of breastexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about N64.2

Is N64.2 billable?

Yes. N64.2 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can N64.2 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict N64.2 as a principal diagnosis.

Is N64.2 a CC or MCC?

No. N64.2 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does N64.2 group to?

N64.2 is used in the MS-DRG v44.0 logic for MS-DRG 600 (Non-Malignant Breast Disorders with CC/MCC) and MS-DRG 601 (Non-Malignant Breast Disorders without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for N64.2?

The CMS General Equivalence Mappings map N64.2 to ICD-9-CM 611.4.