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Dx

ICD-10-CM 2027

ICD-10 code for breast necrosis

N64.1

Fat necrosis of breast

✓ Billable / specificNot a principal dx

From the official ICD-10-CM alphabetic index entry “Necrosis, necrotic (ischemic) › breast (aseptic) (fat) (segmental)”. Page updated September 29, 2026.

About coding breast necrosis

The ICD-10-CM code for breast necrosis is N64.1 (Fat necrosis of breast).

Within N64 (other disorders of breast), N64.1 is specifically for fat necrosis of breast. Related codes cover fissure and fistula of nipple (N64.0), atrophy of breast (N64.2), 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).

Code first: breast necrosis due to breast graft (T85.898).

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

Common questions about breast necrosis ICD-10 codes

What is the ICD-10 code for breast necrosis?

N64.1 — Fat necrosis of breast.

Is N64.1 billable?

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

Can N64.1 be used as a principal diagnosis?

No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

Is N64.1 a CC or MCC?

No. N64.1 is neither a CC nor an MCC under MS-DRG v44.0.