C21
⚠ Non-billable
Malignant neoplasm of anus and anal canal
ICD-10-CM · FY2026 · Neoplasms
Code
C21
System
ICD-10-CM
Billable
No — use specific code
Effective
FY2026
Chapter
Neoplasms
Source
CMS / CDC NCHS
⚠ Verify before billing. Confirm against the current CMS/NCHS ICD-10-CM files and your payer's rules before claims submission.
Official coding notes
From CMS's ICD-10-CM Tabular List.
Excludes2 — not included here, but may code together
- 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)
Frequently asked questions
What is ICD-10 code C21?
ICD-10-CM code C21 represents Malignant neoplasm of anus and anal canal. It is a non-billable header code requiring a more specific subcategory in the Neoplasms chapter, effective October 1, 2025 – September 30, 2026.
Is C21 billable?
No. C21 is a non-billable header. Select a more specific subcategory for claims submission.
What chapter is C21 in?
C21 belongs to the Neoplasms chapter (C00–D49) of ICD-10-CM.
Related codes in the C21 category
Search all 98,186 ICD-10-CM codes instantly
Search ICDwise →