N64.1
Fat necrosis of breast
N64.1 (also written N641) is a billable ICD-10-CM diagnosis code for fat necrosis of breast. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 13 codes in category N64 (Other disorders of breast). The Alphabetic Index lists it under 4 entries. Its coding notes include a Code first instruction, 1 Excludes1 entry and 9 Excludes2 entries.
Code first
If the underlying condition listed here is present and known, sequence it first.
- breast necrosis due to breast graft (T85.898)
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Also from chapter/block level (1 note)
- disorders of breast associated with childbirth (O91-O92)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
- mechanical complication of breast prosthesis and implant (T85.4-)
Also from chapter/block level (8 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- 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)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Gastrointestinal tract and Genitourinary system clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Inclusion terms
Conditions classified to this code.
- Fat necrosis (segmental) of breast
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 4 entries