C21 is a non-billable/non-specific diagnosis code from the 2025 ICD-10-CM used to classify the following condition: Malignant neoplasm of anus and anal canal.
Type 2 excludes
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)
Codes
Versions
2025
No changes
2024
No changes
2023
No changes
2022
No changes
2021
No changes
2020
No changes
2019
No changes
2018
No changes
2017
No changes
2016
New code