Histology Coding Rules: Colon/Rectum
Example: Right colon, villous adenoma and separate 1.5 cm lesion
1) adenocarcinoma in villous adenoma
Answer: 8140/3 Adenocarcinoma
Example: There is a villous adenoma and a separate lesion in the right colon. The histology for the villous adenoma is adenocarcinoma in a villous adenoma, and the histology for the separate lesion is adenocarcinoma. Per rule 2, the adenocarcinoma is coded for histology when there is both a polyp (includes villous adenoma because the first four digits of the ICD-O-3 code are 8261) with adenocarcinoma and a separate lesion with adenocarcinoma in the same colon segment. The histology is adenocarcinoma (8140/3).