ICD-10-CM Alphabetic Index · FY 2026 25 Entries
Mastitis in the ICD-10-CM Index ICD-10-CM
The main term Mastitis (acute) (diffuse) (nonpuerperal) (subacute) carries 25 index entries pointing to 11 ICD-10-CM codes. The default entry is N61.0, the code the bare main term maps to; every indented line below refines the term by site, cause, or type. Verify any candidate code in the Tabular List before using it.
✓ Built from the official CMS FY 2026 index fileEffective Oct 1, 2025 – Sep 30, 2026
25
Index Entries
11
Codes Referenced
N61.0
Default Code
M
Letter
25 of 25 shown
ICD-10-CM
Index Entries Under Mastitis 25 entries · 11 codes
Mastitis (acute) (diffuse) (nonpuerperal) (subacute) N61.0
with abscess N61.1
chronic (cystic) see Mastopathy, cystic
cystic (Schimmelbusch's type) see Mastopathy, cystic
fibrocystic see Mastopathy, cystic
granulomatous N61.2 Non-billable
infective N61.0
newborn P39.0
interstitial, gestational or puerperal see Mastitis, obstetric
neonatal (noninfective) P83.4
infective P39.0
obstetric (interstitial) (nonpurulent)
associated with
lactation O91.23
pregnancy O91.21 Non-billable
puerperium O91.22
purulent
associated with
lactation O91.13
pregnancy O91.11 Non-billable
puerperium O91.12
periductal see Ectasia, mammary duct
phlegmonous see Mastopathy, cystic
plasma cell see Ectasia, mammary duct
without abscess N61.0
The info icon previews the code's description and billable status; the code link opens its full page with all notations.
Related Index Terms
Source: Centers for Medicare & Medicaid Services, FY 2026 ICD-10-CM Index to Diseases and Injuries release files, effective October 1, 2025 through September 30, 2026.
