C21.0Billable

Malignant neoplasm of anus, unspecified

Chapter
2. Neoplasms
Category
C21
Effective date
October 1, 2026

Related codes in category C21

C21Malignant neoplasm of anus and anal canalC21.1Malignant neoplasm of anal canalYesC21.2Malignant neoplasm of cloacogenic zoneYesC21.8Malig neoplasm of ovrlp sites of rectum, anus and anal canalYes

Frequently asked questions

What is ICD-10 code C21.0?

C21.0 is an ICD-10-CM diagnosis code for Malignant neoplasm of anus, unspecified.

Is C21.0 a billable code?

Yes. C21.0 is billable and specific enough to be used on a claim.

What ICD-10-CM chapter is C21.0 in?

C21.0 falls under Chapter 2: Neoplasms.

When did C21.0 become effective?

C21.0 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to C21.0?

C21.0 belongs to category C21, which includes 4 other codes — see the related codes list on this page.

ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.