C18.7 – Malignant neoplasm of sigmoid colon | ICD-10-CM

C18.7 is an ICD-10-CM code used to diagnose malignant neoplasm sigmoid colon. Learn more about this code and how to use it in this comprehensive guide.

By Harriet Murray on Jul 16, 2025.

Fact Checked by RJ Gumban.

Use Code

C18.7 diagnosis code: Malignant neoplasm of sigmoid colon

C18.7 is a billable ICD-10-CM code for healthcare diagnosis reimbursement of malignant neoplasm of sigmoid colon.
The ICD-10-CM version C18.7 is used to diagnose psoriasis vulgaris classified in America. Internationally, the code for the corresponding diagnosis may differ.
C19, or Malignant neoplasm of the rectosigmoid junction, is this code's type 1 excludes note.

It's under the umbrella category of “Neoplasms.” More specifically, it's under “Malignant neoplasm of digestive organs.”
Practitioners can use this code when the patient has a cancerous tumor in the sigmoid colon, the colon section between the descending colon and rectum, in the large intestine

Is C18.7 billable?

Yes. C18.7 is billable for insurance reimbursement purposes.

Clinical information

Malignant neoplasm of sigmoid colon or sigmoid colon cancer is when there are growths or polyps in the inner lining of the patient's colon, particularly the sigmoid colon.
This type of cancer primarily affects people who are 50 years of age or older. However, younger people ranging from 20 to 40 years of age may also be diagnosed with this type of colon cancer, especially if their lifestyle choices increase the risk of developing this disease. Some lifestyle choices that increase the risk are being obese, having a diet that mainly includes red/processed meat, not exercising, and participating in substance abuse, primarily tobacco and alcohol.
Aside from the aforementioned lifestyle choices, medical conditions may also increase the risk of someone developing colon cancer. Some are inherited conditions, polyps or colon cancer history, and inflammatory bowel disease.
Though symptoms may not present themselves in the earlier stages of the disease, later on, when the tumor grows, it may cause the patient to experience the following: blood in stool, abdominal pain, bloating, nausea, vomiting, anemia, pelvic pain, unexplained weight loss, loss of appetite, change in bowel habits, and rectal bleeding. Do note that symptoms may vary depending on the tumor's location.
Diagnosing colon cancer will require the patient to undergo multiple tests. Among them are blood tests, colonoscopy, X-rays, CT scans, MRI scans, PET scans, sigmoidoscopy, and fecal DNA tests.
Treatment varies depending on the stage. Generally, however, treatment can be a mix of surgery and chemotherapy.

Synonyms include

Cancer of the colon, sigmoid
Adenocarcinoma of sigmoid colon
Lymphoma of the sigmoid colon
Malignant tumor of the sigmoid colon
Primary malignant neoplasm of the sigmoid colon

Other ICD-10 codes commonly used for malignant neoplasm of colon

C18.0: Malignant neoplasm of cecum
C18.1: Malignant neoplasm of the appendix
C18.2: Malignant neoplasm of ascending colon
C18.3: Malignant neoplasm of the hepatic flexure
C18.4: Malignant neoplasm of the transverse colon
C18.5: Malignant neoplasm of the splenic flexure
C18.6: Malignant neoplasm of descending colon
C18.7: Malignant neoplasm of signmoid colon
C18.8: Malignant neoplasm of overlapping sites of colon
C18.9: Malignant neoplasm of colon, unspecified

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