title: Detection of micrometastases and skip metastases with ex vivo sentinel node mapping in carcinoma of the colon and rectum.
abstract: BACKGROUND
  The debate over sentinel lymph node mapping (SLNM) and focused pathologic examination to detect micrometastases in patients with colorectal cancer (CRC) continues. We present in this paper our experience with SLNM for CRCs to improve staging. In addition, we have detailed the mapping procedure on an anatomical basis to define skip metastasis.
  
  
  METHODS
  Forty-seven patients underwent ex vivo SLNM. Immediately after resection, 1 ml of patent blue VF was injected submucosally around the tumor. Lymph nodes harvested from the first 15 patients were mapped in a standard fashion as the blue-stained nodes (SLNs), and the others (non-SLNs) were dissected away. In the remaining 32 patients, the lymph nodes were also mapped separately in relation to their anatomic location and described as epicolic-paracolic, intermediate, and principal. The blue-stained nodes (SLNs) and non-SLNs, negative by hematoxylin and eosin stain, were further stained with cytokeratin immunohistochemical analysis and carcinoembryonic antigen.
  
  
  RESULTS
  A total of 873 histologically confirmed LNs were examined with a mean of 18.6+/-8.1 nodes per patient. In 46 of 47 patients (97.8%), SLNs were identified. Immunohistochemical staining revealed micrometastases in the lymph nodes of four patients, which were negative by conventional methods. Anatomical skip metastases were noted in 4 of 32 patients studied (12.5%).
  
  
  CONCLUSIONS
  Ex vivo SLNM in CRCs is a feasible technique with a high SLN identification rate. Results of anatomical mapping of lymph nodes correlates with the limited literature, suggesting that occult skip metastases can occur in the apical lymph node group and may occur outside the resected area.
authors.affiliation: Department of Surgery, Gulhane Military Medical Academy, 06018 Etlik, Ankara, Turkey. gyagci@gata.edu.tr
authors.forename: Gokhan
authors.initials: G
authors.lastname: Yagci
authors.forename: Aytekin
authors.initials: A
authors.lastname: Unlu
authors.forename: Bulent
authors.initials: B
authors.lastname: Kurt
authors.forename: Mehmet Fatih
authors.initials: MF
authors.lastname: Can
authors.forename: Nihat
authors.initials: N
authors.lastname: Kaymakcioglu
authors.forename: Sadettin
authors.initials: S
authors.lastname: Cetiner
authors.forename: Turgut
authors.initials: T
authors.lastname: Tufan
authors.forename: Dervis
authors.initials: D
authors.lastname: Sen
mesh_terms: D000368:Aged; D003082:Colectomy; D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*