C21.8

C21.8: Malignant neoplasm of overlapping sites of rectum, anus and anal canal

Billable / specific codeICD-10-CM

C21.8 is a billable, specific ICD-10-CM code for malignant neoplasm of overlapping sites of rectum, anus and anal canal. It is valid for submission on a claim.

Check C21.8 with the rest of the claim: free scrubber

Inclusion terms

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

Malignant neoplasm of anorectal junction
Malignant neoplasm of anorectum
Primary malignant neoplasm of two or more contiguous sites of rectum, anus and anal canal

Excludes2 inherited from the categories above C21.8

Not part of this code, but both may be coded when both are present.

Written on C21: Malignant neoplasm of anus and anal canal

malignant carcinoid tumors of the colon (C7A.02-)
malignant melanoma of anal margin (C43.51)
malignant melanoma of anal skin (C43.51)
malignant melanoma of perianal skin (C43.51)
other and unspecified malignant neoplasm of anal margin (C44.500, C44.510, C44.520, C44.590)
other and unspecified malignant neoplasm of anal skin (C44.500, C44.510, C44.520, C44.590)
other and unspecified malignant neoplasm of perianal skin (C44.500, C44.510, C44.520, C44.590)

Risk adjustment

C21.8 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. Look up the whole chart to see which of its HCCs the hierarchy would zero.

Medicare coverage

C21.8 is named in 71 Medicare coverage policies: 71 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

A52370Billing and Coding: Bevacizumab and biosimilars
A52450Billing and Coding: Paclitaxel (e.g., Taxol®/Abraxane ™)
A52479Oral Anticancer Drugs - Policy Article
A52480Oral Antiemetic Drugs (Replacement for Intravenous Antiemetics) - Policy Article

Code history

Unchanged in every release from FY2024 to FY2027.