Carcinoma in situ of colon

This code signifies the presence of abnormal, non-invasive cancerous cells confined to the innermost layer (mucosa) of the colon. These cells have not spread beyond the basement membrane and are considered pre-invasive.

Apply this code when pathology reports confirm carcinoma in situ of any part of the colon. This diagnosis is typically made following a colonoscopy with biopsy or polypectomy.

• Differentiate from malignant neoplasm (invasive carcinoma) of the colon, which would be coded to categories 153.x.
• Ensure documentation explicitly states "carcinoma in situ" or "intramucosal carcinoma" without evidence of invasion.
• Do not use for adenomas with high-grade dysplasia unless carcinoma in situ is definitively diagnosed.