2026 ICD-10-CM Diagnosis Code C18.7Malignant neoplasm of sigmoid colon
ICD-10-CM Codes›C00–D49›C15-C26›C18
- Billable — Valid for Submission
- Chronic Condition
C18.7 is a billable ICD-10-CM diagnosis code for malignant neoplasm of sigmoid colon. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 374 through 376. Coders also document this condition as adenocarcinoma of sigmoid colon. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - colorectal.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adenocarcinoma of sigmoid colon
- Carcinoma of sigmoid colon
- Lymphoma of colon
- Lymphoma of sigmoid colon
- Malignant neoplasm of sigmoid colon
- Primary carcinoma of colon
- Primary carcinoma of sigmoid colon
- Primary malignant neoplasm of sigmoid colon
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of sigmoid (flexure)
Type 1 Excludes
- malignant neoplasm of rectosigmoid junction C19
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Malignant Neoplasm of Sigmoid Colon
evidence of a malignant neoplasm of the sigmoid colon.Malignant Sigmoid Colon Neoplasm|Malignant Neoplasm of Sigmoid Colon|Malignant neoplasm of sigmoid colon
a primary or metastatic malignant neoplasm that affects the sigmoid colon.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| intestine, intestinal › large › colon › pelvic | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › sigmoid (flexure) | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| intestine, intestinal › large › sigmoid flexure (lower) (upper) | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| sigmoid flexure (lower) (upper) | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
Patient EducationClinical
Colorectal Cancer
Colorectal cancer is cancer that develops in the tissues of the colon or rectum. Your colon and rectum are part of your digestive system:
The full article covers:
- What is colorectal cancer?
- What causes colorectal cancer?
- Who is more likely to develop colorectal cancer?
- What are the symptoms of colorectal cancer?
- What is screening for colorectal cancer and who needs it?
- How is colorectal cancer diagnosed?
- What are the treatments for colorectal cancer?
- Can colorectal cancer be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C18.7 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C18.7Overview
Is C18.7 (Malignant neoplasm of colon) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of sigmoid colon on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C18.7 group to?
When malignant neoplasm of sigmoid colon is the principal diagnosis on an inpatient stay, it groups to MS-DRG 374, 375, 376, with relative weights from 0.9243 to 2.1387 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C18.7?
Under the General Equivalence Mappings, malignant neoplasm of sigmoid colon converts to ICD-9-CM 153.3 (mal neo sigmoid colon). The mapping is a direct match.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
