Colorectal Cancer: Extension
Ignore intraluminal extension
Definition of tumor nodule vs. lymph node mets
Codes 60–80 code contiguous (direct) extension
Discontinuous involvement is coded in Mets at Dx
Three descriptive notes are included in the coding instructions for CS extension of colon and rectum.
Rule 1: When assigning extension, ignore intraluminal tumor extension from one segment to adjacent segments or intraluminal extension to the ileum from the cecum.
Rule 2: If a tumor nodule is found in the pericolic fat or adipose tissue and it does not include histologic evidence of residual lymph node but is does have the form and smooth contour of a lymph node, it should be coded as regional lymph node metastasis; however if it has an irregular contour, it should be coded in CS extension as code 45.
Rule 3: Extension codes 60–80 indicate regional and distant contiguous tumor spread. Discontinuous involvement is coded in CS mets at dx.