ICD-10-CM Table of Neoplasms · FY 2026 Letter I

Table of Neoplasms: Anatomical Sites Starting With I ICD-10-CM

The letter I section of the FY 2026 Table of Neoplasms covers 62 anatomical site entries under 26 top-level anatomical sites. Each row carries up to six ICD-10-CM codes, one per behavior column, and sub-entries are indented under their parent exactly as the printed CMS table nests them.

✓ Built from the official CMS FY 2026 datasetEffective Oct 1, 2025 – Sep 30, 2026
62
Anatomical site Entries
26
Top-Level Anatomical sites
6
Code Columns
I
Letter
Column 1
Malignant Primary
Cancer at site of origin
Column 2
Malignant Secondary
Metastatic spread
Column 3
Ca In Situ
Non-invasive, early stage
Column 4
Benign
Non-cancerous
Column 5
Uncertain Behavior
Behavior undeterminable
Column 6
Unspecified Behavior
Behavior not documented
ABCDEFGHIJKLMNOPRSTUVWXZ
ICD-10-CM

Table of Neoplasms: I 62 entries

62 of 62 shown
Anatomical SiteMalignant
Primary
Malignant
Secondary
Ca
In Situ
BenignUncertain
Behavior
Unspecified
Behavior
ileocecum, ileocecal (coil) (junction) (valve)C18.0C78.5D01.0D12.0D37.4D49.0
ileumC17.2C78.4D01.49D13.39D37.2D49.0
iliumC41.4C79.51D16.8D48.0D49.2
immunoproliferative NECC88.9
infraclavicular (region)C76.1C79.89D04.5D36.7D48.7D49.89
inguinal (region)C76.3C79.89D04.5D36.7D48.7D49.89
insulaC71.0C79.31D33.0D43.0D49.6
insular tissue (pancreas)C25.4C78.89D01.7D13.7D37.8D49.0
brainC71.0C79.31D33.0D43.0D49.6
interarytenoid foldC13.1C79.89D00.08D10.7D37.05D49.0
hypopharyngeal aspectC13.1C79.89D00.08D10.7D37.05D49.0
laryngeal aspectC32.1C78.39D02.0D14.1D38.0D49.1
marginal zoneC13.1C79.89D00.08D10.7D37.05D49.0
interdental papillaeC03.9C79.89D00.03D10.39D37.09D49.0
lowerC03.1C79.89D00.03D10.39D37.09D49.0
upperC03.0C79.89D00.03D10.39D37.09D49.0
internalC71.0C79.31D33.0D43.0D49.6
capsuleC71.0C79.31D33.0D43.0D49.6
os (cervix)C53.0C79.82D06.0D26.0D39.0D49.59
intervertebral cartilage or discC41.2C79.51D16.6D48.0D49.2
intestine, intestinalC26.0C78.80D01.40D13.99D37.8D49.0
largeC18.9C78.5D01.0D12.6D37.4D49.0
appendixC18.1C78.5D01.0D12.1D37.3D49.0
caput coliC18.0C78.5D01.0D12.0D37.4D49.0
cecumC18.0C78.5D01.0D12.0D37.4D49.0
colonC18.9C78.5D01.0D12.6D37.4D49.0
and rectumC19C78.5D01.1D12.7D37.5D49.0
ascendingC18.2C78.5D01.0D12.2D37.4D49.0
caputC18.0C78.5D01.0D12.0D37.4D49.0
descendingC18.6C78.5D01.0D12.4D37.4D49.0
distalC18.6C78.5D01.0D12.4D37.4D49.0
leftC18.6C78.5D01.0D12.4D37.4D49.0
overlapping lesionC18.8
pelvicC18.7C78.5D01.0D12.5D37.4D49.0
rightC18.2C78.5D01.0D12.2D37.4D49.0
sigmoid (flexure)C18.7C78.5D01.0D12.5D37.4D49.0
transverseC18.4C78.5D01.0D12.3D37.4D49.0
hepatic flexureC18.3C78.5D01.0D12.3D37.4D49.0
ileocecum, ileocecal (coil) (valve)C18.0C78.5D01.0D12.0D37.4D49.0
overlapping lesionC18.8
sigmoid flexure (lower) (upper)C18.7C78.5D01.0D12.5D37.4D49.0
splenic flexureC18.5C78.5D01.0D12.3D37.4D49.0
smallC17.9C78.4D01.40D13.30D37.2D49.0
duodenumC17.0C78.4D01.49D13.2D37.2D49.0
ileumC17.2C78.4D01.49D13.39D37.2D49.0
jejunumC17.1C78.4D01.49D13.39D37.2D49.0
overlapping lesionC17.8
tract NECC26.0C78.89D01.40D13.99D37.8D49.0
intra-abdominalC76.2C79.89D09.8D36.7D48.7D49.89
intracranial NECC71.9C79.31D33.2D43.2D49.6
intrahepatic (bile) ductC22.1C78.7D01.5D13.4D37.6D49.0
intraocularC69.9C79.49D09.2D31.9D48.7D49.89
intraorbitalC69.6C79.49D09.2D31.6D48.7D49.89
intrasellarC75.1C79.89D09.3D35.2D44.3D49.7
intrathoracic (cavity) (organs)C76.1C79.89D09.8D15.9D48.7D49.89
specified NECC76.1C79.89D09.8D15.7
irisC69.4C79.49D09.2D31.4D48.7D49.89
ischiorectal (fossa)C76.3C79.89D09.8D36.7D48.7D49.89
ischiumC41.4C79.51D16.8D48.0D49.2
island of ReilC71.0C79.31D33.0D43.0D49.6
islands or islets of LangerhansC25.4C78.89D01.7D13.7D37.8D49.0
isthmus uteriC54.0C79.82D07.0D26.1D39.0D49.59

Indented rows are sub-entries of the entry above them. The filter matches the full path, so typing a parent term finds its sub-entries too.

Questions About This Page

How do I pick the right column?

The pathology or clinical documentation names the behavior. When the description of the neoplasm names the behavior, that description overrides the Index guidance, and the matching column supplies the code.

Why are some cells empty?

Not every site has a code for every behavior. An empty cell means the classification does not provide a code in that column for that site, and the parent row or the main Index should be consulted.

Related References

Source: official CMS FY 2026 ICD-10-CM release, effective October 1, 2025 through September 30, 2026.