| C21.0 | Malignant neoplasm of anus, unspecified | BILLABLE CODE |
| C21.1 | Malignant neoplasm of anal canal | BILLABLE CODE |
| C21.2 | Malignant neoplasm of cloacogenic zone | BILLABLE CODE |
| C21.8 | Malignant neoplasm of overlapping sites of rectum, anus and anal canal | BILLABLE CODE |
