Malignant neoplasm of cloacogenic zone

This code signifies a cancerous tumor originating in the cloacogenic zone of the anorectum. This specific area is a transitional zone located between the columnar epithelium of the rectum and the squamous epithelium of the anal canal, often referred to as the anal transitional zone.

Use this code when documentation explicitly states a malignant neoplasm of the cloacogenic zone or anal transitional zone. This diagnosis is typically confirmed by biopsy and pathology reports. It is crucial to differentiate this from other anal or rectal cancers.

• Ensure the pathology report specifically identifies the cloacogenic zone as the origin of the malignancy.
• Do not use this code for squamous cell carcinoma of the anal canal or adenocarcinoma of the rectum, which have distinct codes.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter, followed by any relevant secondary diagnoses.