C18.6 – Malignant neoplasm of descending colon

ICD-10-CM 2027 diagnosis code · Malignant neoplasms of digestive organs

Billable code

ICD-10-CM code C18.6

Code: C18.6 (claims format: C186)
Description: Malignant neoplasm of descending colon
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 2. Neoplasms (C00-D49)
Block: C15-C26 Malignant neoplasms of digestive organs
Parent codes: C18

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

C18 – Malignant neoplasm of colon

Excludes1 (not coded here):

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

Block C15-C26

Excludes1 (not coded here):

Kaposi's sarcoma of gastrointestinal sites (C46.4)

Excludes2 (not included here):

gastrointestinal stromal tumors (C49.A-)

Related codes in C18

C18.0 – Malignant neoplasm of cecumBillable
C18.1 – Malignant neoplasm of appendixBillable
C18.2 – Malignant neoplasm of ascending colonBillable
C18.3 – Malignant neoplasm of hepatic flexureBillable
C18.4 – Malignant neoplasm of transverse colonBillable
C18.5 – Malignant neoplasm of splenic flexureBillable
C18.7 – Malignant neoplasm of sigmoid colonBillable
C18.8 – Malignant neoplasm of overlapping sites of colonBillable
C18.9 – Malignant neoplasm of colon, unspecifiedBillable

Frequently asked questions

What is ICD-10 code C18.6?

C18.6 is the ICD-10-CM code for malignant neoplasm of descending colon, in the block C15-C26 (Malignant neoplasms of digestive organs).

Is C18.6 a billable code?

Yes. C18.6 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does C18.6 belong to?

It belongs to category C18 – Malignant neoplasm of colon.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.