2026 ICD-10-CM Diagnosis Code C78.5Secondary malignant neoplasm of large intestine and rectum
ICD-10-CM Codes›C00–D49›C76-C80›C78
- Billable — Valid for Submission
- Chronic Condition
ICD-10-CM C78.5
C78.5 is a billable ICD-10-CM diagnosis code for secondary malignant neoplasm of large intestine and 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 Secondary malignancies.
Code Identity
ICD-10-CM Code
C78.5
Billable Status
Yes — Valid for Submission
Code Describes
Secondary malignant neoplasm of large intestine and rectum
Short Description
Secondary malignant neoplasm of large intestine and rectum
Same as the full description in the CMS dataset.
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Malignant neoplasm of cecum
- Malignant neoplasm of hepatic flexure of colon
- Malignant neoplasm of rectosigmoid junction
- Malignant neoplasm of rectum, rectosigmoid junction and anus
- Malignant neoplasm of splenic flexure
- Malignant tumor involving rectum by direct extension from endometrium
- Malignant tumor involving rectum by direct extension from fallopian tube
- Malignant tumor involving rectum by direct extension from ovary
- Malignant tumor involving rectum by direct extension from prostate
- Malignant tumor involving rectum by direct extension from uterine cervix
- Malignant tumor involving rectum by direct extension from uterus
- Malignant tumor involving rectum by direct extension from vagina
- Metastatic carcinoma to anal canal
- Metastatic carcinoma to ascending colon
- Metastatic carcinoma to cecum
- Metastatic carcinoma to colon
- Metastatic carcinoma to descending colon
- Metastatic carcinoma to hepatic flexure
- Metastatic carcinoma to rectosigmoid junction
- Metastatic carcinoma to sigmoid colon
- Metastatic carcinoma to splenic flexure
- Metastatic carcinoma to transverse colon
- Metastatic malignant neoplasm to anal canal
- Metastatic malignant neoplasm to anus
- Metastatic malignant neoplasm to appendix
- Metastatic malignant neoplasm to ascending colon
- Metastatic malignant neoplasm to cecum
- Metastatic malignant neoplasm to colon
- Metastatic malignant neoplasm to colorectum
- Metastatic malignant neoplasm to descending colon
- Metastatic malignant neoplasm to hepatic flexure of colon
- Metastatic malignant neoplasm to large intestine
- Metastatic malignant neoplasm to rectosigmoid junction
- Metastatic malignant neoplasm to rectum
- Metastatic malignant neoplasm to sigmoid colon
- Metastatic malignant neoplasm to splenic flexure of colon
- Metastatic malignant neoplasm to transverse colon
- Metastatic squamous cell carcinoma to rectum
- Neoplasm of hepatic flexure of colon
- Neoplasm of splenic flexure of colon
- Radiologic finding of tumor invasion penetrating colonic serosa
- Rectum involved by direct extension of malignant neoplasm
- Squamous cell carcinoma of rectum
- Tumor invades beyond pancreatic capsule to adjacent structures AND/OR organs
- Tumor invades beyond pancreatic capsule to colon
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
CCSR NEO070
Secondary malignancies
Default principal diagnosis: inpatient Yes · outpatient Yes
Clinical InformationClinical
Appendiceal Neoplasms
tumors or cancer of the appendix.Appendix
a worm-like blind tube extension from the cecum.Colon
the segment of large intestine between the cecum and the rectum. it includes the ascending colon; the transverse colon; the descending colon; and 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. |
|---|---|---|---|---|---|---|
| anorectum, anorectal (junction) | C21.8 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| anus, anal | C21.0 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| anus, anal › canal | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| anus, anal › cloacogenic zone | C21.2 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| anus, anal › sphincter | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| appendix | C18.1 | C78.5 | D01.0 | D12.1 | D37.3 | D49.0 |
| canal | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| canal › anal | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| caput coli | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| cecum | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| cloacogenic zone | C21.2 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| colon [See Also: Neoplasm, intestine, large] | C18.9 | C78.5 | – | – | – | – |
| colon [See Also: Neoplasm, intestine, large] › with rectum | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| crypt of Morgagni | C21.8 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| hemorrhoidal zone | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| hepatic [See Also: Index to disease, by histology] › flexure (colon) | C18.3 | C78.5 | D01.0 | D12.3 | D37.4 | D49.0 |
| ileocecum, ileocecal (coil) (junction) (valve) | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| intestine, intestinal › large | C18.9 | C78.5 | D01.0 | D12.6 | D37.4 | D49.0 |
| intestine, intestinal › large › appendix | C18.1 | C78.5 | D01.0 | D12.1 | D37.3 | D49.0 |
| intestine, intestinal › large › caput coli | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| intestine, intestinal › large › cecum | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| intestine, intestinal › large › colon | C18.9 | C78.5 | D01.0 | D12.6 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › and rectum | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| intestine, intestinal › large › colon › ascending | C18.2 | C78.5 | D01.0 | D12.2 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › caput | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › descending | C18.6 | C78.5 | D01.0 | D12.4 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › distal | C18.6 | C78.5 | D01.0 | D12.4 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › left | C18.6 | C78.5 | D01.0 | D12.4 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › pelvic | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| intestine, intestinal › large › colon › right | C18.2 | C78.5 | D01.0 | D12.2 | 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 › colon › transverse | C18.4 | C78.5 | D01.0 | D12.3 | D37.4 | D49.0 |
| intestine, intestinal › large › hepatic flexure | C18.3 | C78.5 | D01.0 | D12.3 | D37.4 | D49.0 |
| intestine, intestinal › large › ileocecum, ileocecal (coil) (valve) | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| intestine, intestinal › large › sigmoid flexure (lower) (upper) | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| intestine, intestinal › large › splenic flexure | C18.5 | C78.5 | D01.0 | D12.3 | D37.4 | D49.0 |
| junction | C21.8 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| junction › anorectal | C21.8 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| junction › ileocecal | C18.0 | C78.5 | D01.0 | D12.0 | D37.4 | D49.0 |
| junction › pelvirectal | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| junction › rectosigmoid | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| pelvirectal junction | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| rectosigmoid (junction) | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| rectum (ampulla) | C20 | C78.5 | D01.2 | D12.8 | D37.5 | D49.0 |
| rectum (ampulla) › and colon | C19 | C78.5 | D01.1 | D12.7 | D37.5 | D49.0 |
| sigmoid flexure (lower) (upper) | C18.7 | C78.5 | D01.0 | D12.5 | D37.4 | D49.0 |
| sphincter | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| sphincter › anal | C21.1 | C78.5 | D01.3 | D12.9 | D37.8 | D49.0 |
| spleen, splenic NEC › flexure (colon) | C18.5 | C78.5 | D01.0 | D12.3 | 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?
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Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C78.5 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.
Questions About C78.5Overview
Is C78.5 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report secondary malignant neoplasm of large intestine and rectum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C78.5 group to?
When secondary malignant neoplasm of large intestine and 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 C78.5?
Under the General Equivalence Mappings, secondary malignant neoplasm of large intestine and rectum converts to ICD-9-CM 197.5 (sec malig neo lg bowel). 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.
