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  6. 2024 ICD-10-CM Code C21
Version 2024
Non-Billable Code

2024 ICD-10-CM Diagnosis Code C21

Malignant neoplasm of anus and anal canal

ICD-10-CM Code:
C21
ICD-10 Code for:
Malignant neoplasm of anus and anal canal
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Neoplasms
    (C00–D49)
    • Malignant neoplasms of digestive organs
      (C15-C26)
      • Malignant neoplasm of anus and anal canal
        (C21)

C21 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of malignant neoplasm of anus and anal canal. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Malignant neoplasm of anus and anal canal

Non-specific codes like C21 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for malignant neoplasm of anus and anal canal:

  • Use C21.0 for Malignant neoplasm of anus, unspecified - BILLABLE CODE

  • Use C21.1 for Malignant neoplasm of anal canal - BILLABLE CODE

  • Use C21.2 for Malignant neoplasm of cloacogenic zone - BILLABLE CODE

  • Use C21.8 for Malignant neoplasm of overlapping sites of rectum, anus and anal canal - BILLABLE CODE

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

Patient Education


Anal Cancer

The anus is where stool leaves your body when you go to the bathroom. It is made up of your outer layers of skin and the end of your large intestine. Anal cancer is a disease in which cancer cells form in the tissues of the anus.

Anal cancer is rare. It is more common in smokers and people over 50. You are also at higher risk if you have HPV, have anal sex, or have many sexual partners.

Symptoms include bleeding, pain, or lumps in the anal area. Anal itching and discharge can also be signs of anal cancer.

Doctors use tests that examine the anus to diagnose anal cancer. They include a physical exam, endoscopy, ultrasound, and biopsy.

Treatments include radiation therapy, chemotherapy, and surgery.

NIH: National Cancer Institute


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.