C21 - Malignant neoplasm of anus and anal canal
Excludes 2:
-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)
C21.0 - Malignant neoplasm of anus, unspecified
C21.1 - Malignant neoplasm of anal canal
C21.2 - Malignant neoplasm of cloacogenic zone
C21.8 - Malignant neoplasm of overlapping sites of rectum, anus and anal canal