Non-Billable / Non-Specific Code
ICD-10-CM C21 is the diagnosis code for Malignant neoplasm of anus and anal canal. This code falls under the section "Malignant neoplasms of digestive organs" within Chapter 2 â Neoplasms (C00-D49). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions are not included in C21. If the patient has both, code each condition separately:
Understanding where C21 sits in the ICD-10-CM classification helps ensure proper coding:
No, C21 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
C21 is the ICD-10-CM diagnosis code for "Malignant neoplasm of anus and anal canal". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
C21 is located in Section C15-C26 â "Malignant neoplasms of digestive organs" within Chapter 2 of the ICD-10-CM Tabular List.
C21 has 4 sub-code(s) that provide more specific detail: C21.0, C21.1, C21.2, C21.8.
Use C21 when the patients documented diagnosis matches "Malignant neoplasm of anus and anal canal" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Malignant neoplasm of anus and anal canal is C21.
No, C21 is non-billable. Use a more specific sub-code for primary diagnosis billing.
C21 is in Chapter 2 of the ICD-10-CM Tabular List.
Yes, C21 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.