N62 vs P83.4
N62 and P83.4 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on N62
breast engorgement of newborn (P83.4)
N62
Hypertrophy of breast
Billable
- Chapter 14
- Diseases of the genitourinary system
- Section
- N60-N65
Use when the record says
- Gynecomastia
- Hypertrophy of breast NOS
- Massive pubertal hypertrophy of breast
Indexed under
- Gynecomastia
- Mammoplasia
- Mastoplasia, mastoplastia
- Excess, excessive, excessively › development, breast
- Hypertrophy, hypertrophic › breast
P83.4
Breast engorgement of newborn
Billable
- Chapter 16
- Certain conditions originating in the perinatal period
- Section
- P80-P83
Use when the record says
- Noninfective mastitis of newborn
Indexed under
- Mastitis › neonatal (acute) (diffuse) (nonpuerperal) (subacute)
- Newborn › breast engorgement (infant) (liveborn) (singleton)
- Engorgement › breast › newborn
- Hypertrophy, hypertrophic › breast › newborn
- Newborn › mastitis › noninfective (infant) (liveborn) (singleton)
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027