Coding Behavior for Colon/Rectum
Synonyms for in situ, behavior code 2
Intramucosal is not in situ behavior
Tis for AJCC stage
Local for SS77 and SS2000
Behavior code 3 for ICD-O-3 histology code
For colon/rectum, intraepithelial and noninvasive are synonyms for in situ. Tumors described histologically as intraepithelial or noninvasive should be coded with ICD- O-3 behavior code 2 (in situ). Even though tumors described as intramucosal are categorized in AJCC stage as Tis, the ICD-O-3 behavior is not in situ (2). Intramucosal is not a synonym for in situ. The behavior code for intramucosal tumors of the colon and rectum is malignant (3), and the stage for SS77 and SS2000 is local.