Malignant neoplasm of anal canal

This code signifies a primary cancerous tumor originating in the anal canal, the terminal section of the large intestine connecting the rectum to the anus. This malignancy can involve various cell types, most commonly squamous cell carcinoma, but also adenocarcinoma or melanoma.

Use this code when documentation confirms a primary malignant neoplasm of the anal canal, typically identified through biopsy and pathology reports. This code is appropriate for initial diagnosis, treatment planning, and follow-up care for this specific cancer.

• Differentiate from malignant neoplasms of the rectum (154.0) or anus, unspecified (154.3).
• Ensure documentation specifies "anal canal" to avoid confusion with perianal skin cancers.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter.