C21: Malignant neoplasm of anus and anal canal
C21.1: Malignant neoplasm: Anal canal
The tissue in the body is made up of cells. With cancer, the cells multiply uncontrollably, which leads to a malignant neoplasm (abnormal growth of tissue) developing. The cancer cells can destroy the healthy tissue and spread throughout the body.
The last segment of the large intestine consists of 2 sections. These 2 sections are the rectum and anal canal. The feces are collected in the rectum. The feces then move through the short anal canal to the anus. Feces are excreted through the anus. The anus is located at the end of the intestines and is ring-shaped. A sphincter muscle in the last segment of the intestines ensures that we only intentionally excrete feces through the anus.
You have cancer of the anal canal.
Please note: This ICD code may also derive from the ICD-O system. If this is the case, there are usually additional letters and numbers in addition to the code. It starts with the letter M, followed by 4 digits and then a slash. There is another digit after the slash.
If it is an ICD-O code, then this does not describe a malignant cancer in all cases. The last digit after the slash gives you more detailed information about this:
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