C21 — Malignant neoplasm of anus and anal canal
Is C21 billable?
No — C21 is a non-billable header code. C21 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 4 billable codes beneath C21.
C21 at a glance
| Code | C21 |
|---|---|
| Description | Malignant neoplasm of anus and anal canal |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Excludes2 — not included here
The conditions below are not part of C21, but a patient may have both at the same time. When documentation supports it, C21 and the excluded code may both be reported.
- 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)
Excludes1 — never code together — inherited from C15-C26
The conditions below can never be reported together with C21 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- Kaposi's sarcoma of gastrointestinal sites (C46.4)
Excludes2 — not included here — inherited from C15-C26
The conditions below are not part of C21, but a patient may have both at the same time. When documentation supports it, C21 and the excluded code may both be reported.
- gastrointestinal stromal tumors (C49.A-)
What codes fall under C21? (4)
How long has C21 existed?
C21 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.