N64.1 Fat necrosis of breast

Billable ICD-10-CM code, FY2026.

Applicable to

• Fat necrosis (segmental) of breast

Code first

• breast necrosis due to breast graft (T85.898)

Applies from N64 Other disorders of breast

Excludes2 (not included here)

• mechanical complication of breast prosthesis and implant (T85.4-)

MS-DRG index

Defines the logic of DRG(s) 600-601 in MDC 09.

Approximate ICD-9-CM (GEMs)

• 611.3 Fat necrosis of breast

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Diagnosis Index entries for N64.1

• Fat › necrosis › breast
• Necrosis, necrotic (ischemic) › breast (aseptic) (fat) (segmental)
• Necrosis, necrotic (ischemic) › fat, fatty (generalized) › breast (aseptic) (segmental)
• Necrosis, necrotic (ischemic) › mammary gland (fat) (segmental)

Nearby codes

• N64 Other disorders of breast
• N64.0 Fissure and fistula of nipple
• N64.1 Fat necrosis of breast (this code)
• N64.2 Atrophy of breast
• N64.3 Galactorrhea not associated with childbirth
• N64.4 Mastodynia
• N64.5 Other signs and symptoms in breast
• N64.51 Induration of breast