Malignant neoplasm of rectosigmoid junction
In Malignant neoplasms of digestive organs (C15-C26), chapter 2: Neoplasms
- C19 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under C15-C26 below.
- As a secondary diagnosis it is a CC (complication or comorbidity), which can raise the MS-DRG payment. It doesn't count when the principal diagnosis is one of 21 closely related codes.
- Counts toward HCC 22 (Bladder, Colorectal, and Other Cancers) in the Medicare Advantage risk model (CMS-HCC V28).
- AHRQ's Chronic Condition Indicator classes it as chronic: expected to last 12 months or longer and to limit daily life or need ongoing care.
- 3,878 US deaths in 2024 had an underlying cause in category C19, per the National Vital Statistics System on CDC WONDER. Death records use WHO ICD-10, so the count is for the whole category.
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Instructional notes
Includes: conditions that are coded here
- Malignant neoplasm of colon with rectum
- Malignant neoplasm of rectosigmoid (colon)
Excludes1: not coded here, use a different code
- malignant carcinoid tumors of the colon (C7A.02-)
Also applies, from Malignant neoplasms of digestive organs (C15-C26)
These notes sit on C15-C26 and apply to every code under it, including C19.
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Rules for coding benign and malignant neoplasms: using the Neoplasm Table, sequencing primary and secondary sites, treatment encounters, complications, and current cancer versus personal history.
- Admission/Encounter for treatment of primary site (page 33)
- Admission/Encounter for treatment of secondary site (page 33)
- Coding and sequencing of complications (page 34)
- Primary malignancy previously excised (page 34)
- Admissions/Encounters involving antineoplastic chemotherapy, immunotherapy and radiation therapy (page 35)
- Admission/encounter to determine extent of malignancy (page 36)
- Symptoms, signs, and abnormal findings listed in Chapter 18 associated with neoplasms (page 36)
- Admission/encounter for pain control/management (page 36)
Other codes under C15-C26
Malignant neoplasms of digestive organs (C15-C26)
- C15Malignant neoplasm of esophagus
- C16Malignant neoplasm of stomach
- C17Malignant neoplasm of small intestine
- C18Malignant neoplasm of colon
- C19Malignant neoplasm of rectosigmoid junction(this code)
- C20Malignant neoplasm of rectum
- C21Malignant neoplasm of anus and anal canal
- C22Malignant neoplasm of liver and intrahepatic bile ducts
- C23Malignant neoplasm of gallbladder
- C24Malignant neoplasm of other and unspecified parts of biliary tract
- C25Malignant neoplasm of pancreas
- C26Malignant neoplasm of other and ill-defined digestive organs
C19 MS-DRGs
As the principal diagnosis, C19 groups to MS-DRG 374, 375, or 376 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
Related conditions
Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.
C19 is in Gastrointestinal cancers - colorectal (NEO015, its default category), with 19 codes. Others in it:
- C18.0 Malignant neoplasm of cecum
- C18.1 Malignant neoplasm of appendix
- C18.2 Malignant neoplasm of ascending colon
- C18.3 Malignant neoplasm of hepatic flexure
- C18.4 Malignant neoplasm of transverse colon
- C18.5 Malignant neoplasm of splenic flexure
- C18.6 Malignant neoplasm of descending colon
- C18.7 Malignant neoplasm of sigmoid colon
Medicare coverage articles listing C19
These 43 Medicare billing and coding articles list C19 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.
- MolDX: FDA-Approved BRAF Tests (4 contractors)
- MolDX: Genetic Testing for Hereditary Thrombophilia (4 contractors)
- MolDX: Lab-Developed Tests for Inherited Cancer Syndromes in Patients with Cancer (4 contractors)
- MolDX: Minimal Residual Disease Testing for Solid Tumor Cancers (4 contractors)
- MolDX: NRAS Genetic Testing (4 contractors)
- MolDX: Next-Generation Sequencing for Solid Tumors (4 contractors)
- MolDX: Non-Next Generation Sequencing Targeted Molecular Panel Tests for Targeted Therapy in Cancer (4 contractors)
- MolDX: Plasma-Based Genomic Profiling in Solid Tumors (4 contractors)
- Colonoscopy/Sigmoidoscopy/Proctosigmoidoscopy (2 contractors)
- Erythropoiesis Stimulating Agents (2 contractors)
And 33 more.
Other codes that refer to C19
Notes on these codes point to C19.
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
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: Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer that affects either of these parts may also be called colorectal cancer.
Read more about colorectal cancer on MedlinePlusCode history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.
ICD-9-CM equivalent
Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).
- 154.0 Malignant neoplasm of rectosigmoid junction