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C20

C20Malignant neoplasm of rectum

Billable / specific codeICD-10-CM

C20 is a billable, specific ICD-10-CM code for malignant neoplasm of rectum. It is valid for submission on a claim.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

  • malignant carcinoid tumor of the rectum (C7A.026)

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Malignant neoplasm of rectal ampulla

Risk adjustment

C20 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 22 Bladder, Colorectal, and Other Cancers0.363 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

C20 is named in 112 Medicare coverage policies 112 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

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Questions about C20

Is C20 a billable ICD-10-CM code?
Yes. C20 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C20 sit in the tabular list?
Neoplasms (C00-D49), in the block Malignant neoplasms of digestive organs (C15-C26).
What cannot be coded together with C20?
C20 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.