2026 ICD-10-CM Diagnosis Code C20Malignant neoplasm of rectum
ICD-10-CM Codes›C00–D49›C15-C26›C20
- Billable — Valid for Submission
- Chronic Condition
C20 is a billable ICD-10-CM diagnosis code for malignant neoplasm of rectum. 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. 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 rectum
- Anorectal adenocarcinoma
- Carcinoma of upper rectum
- Leiomyosarcoma of rectum
- Local recurrence of malignant neoplasm of rectum
- Malignant melanoma of rectum
- Malignant neoplasm of rectum
- Overlapping malignant neoplasm of colon
- Overlapping malignant neoplasm of colon and rectum
- Primary malignant mesenchymal neoplasm of rectum
- Primary malignant neoplasm of rectum
- Primary squamous cell carcinoma of rectum
- Squamous cell carcinoma of rectum
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of rectal ampulla
Type 1 Excludes
- malignant carcinoid tumor of the rectum C7A.026
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.
Table of NeoplasmsClinical
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 C20 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C20Overview
Is C20 (Malignant neoplasm of rectum) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of rectum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C20 group to?
When malignant neoplasm of rectum 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 C20?
Under the General Equivalence Mappings, malignant neoplasm of rectum converts to ICD-9-CM 154.1 (malignant neopl rectum). 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.
