C18
ICD-10Non-billable categoryMalignant neoplasm of colon
Official ICD-10-CM descriptor (FY2026)
Malignant neoplasm of colon
C18 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Excludes1
Not coded here. An Excludes1 code should never be reported at the same time as the code above it.
- malignant carcinoid tumors of the colon (C7A.02-)
More specific codes under C18
- C18.0Malignant neoplasm of cecum
- C18.1Malignant neoplasm of appendix
- C18.2Malignant neoplasm of ascending colon
- C18.3Malignant neoplasm of hepatic flexure
- C18.4Malignant neoplasm of transverse colon
- C18.5Malignant neoplasm of splenic flexure
- C18.6Malignant neoplasm of descending colon
- C18.7Malignant neoplasm of sigmoid colon
- C18.8Malignant neoplasm of overlapping sites of colon
- C18.9Malignant neoplasm of colon, unspecified
Where this code sits
- Chapter
- 2. Neoplasms (C00-D49)
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.