U.S. ICD-10-CM · FY 2027

C18 ICD-10-CM Code: Malignant neoplasm of colon

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

C18

Malignant neoplasm of colon

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where C18 sits

  1. 1

    Chapter 2

    Neoplasms (C00-D49)

  2. 2

    Section

    Malignant neoplasms of digestive organs (C15-C26)

  3. 3

    Category C18

    Malignant neoplasm of colon

  4. 4

    Code C18

    Malignant neoplasm of colon

More specific choices

Codes under C18

C18 is a non-billable category. Choose the child code that best matches the documented diagnosis.

C18.0

Malignant neoplasm of cecum

C18.1

Malignant neoplasm of appendix

C18.2

Malignant neoplasm of ascending colon

C18.3

Malignant neoplasm of hepatic flexure

C18.4

Malignant neoplasm of transverse colon

C18.5

Malignant neoplasm of splenic flexure

C18.6

Malignant neoplasm of descending colon

C18.7

Malignant neoplasm of sigmoid colon

C18.8

Malignant neoplasm of overlapping sites of colon

C18.9

Malignant neoplasm of colon, unspecified

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for C18.

Code first

No “code first” instruction is listed for C18.

Use additional code

No “use additional code” instruction is listed for C18.

Excludes1

Conditions that should not be reported together with this code.

  • malignant carcinoid tumors of the colon (C7A.02-)

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for C18.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

Publisher

Vero Scribe Inc.

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code C18 mean?

C18 is the FY 2027 U.S. ICD-10-CM code for “Malignant neoplasm of colon.”

Is C18 a billable or specific ICD-10-CM code?

No. C18 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is C18 located in ICD-10-CM?

C18 is listed in Chapter 2, Neoplasms (C00-D49), within Malignant neoplasms of digestive organs (C15-C26) (C15–C26), under category C18, Malignant neoplasm of colon.

What coding notes are listed for C18?

No inclusion terms are listed for C18 in this reference record. No code-first instruction is listed. Excludes1 notes: malignant carcinoid tumors of the colon (C7A.02-). No Excludes2 note is listed.

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