Colorectal carcinoma nodal staging. Frequency and nature of cytokeratin-positive cells in sentinel and nonsentinel lymph nodes

Nodal staging accuracy is important for prognosis and selection of patients for chemotherapy. Sentinel lymph node (SLN) mapping improves staging accuracy in breast cancer and melanoma and is being investigated for colorectal carcinoma. To assess pathologic aspects of SLN staging for colon cancer. Sentinel lymph nodes were identified with a dual surgeon-pathologist technique in 51 colorectal carcinomas and 12 adenomas. The frequency of cytokeratin (CK)-positive cells in mesenteric lymph nodes, both SLN and non-SLN, was determined along with their immunohistochemical characteristics. The median number of SLNs was 3; the median number of total nodes was 14. The CK-positive cell clusters were detected in the SLNs of 10 (29%) of 34 SLN-negative patients. Adjusted per patient, SLNs were significantly more likely to contain CK-positive cells than non-SLNs (P