title: Effect of xylene clearance of mesenteric fat on harvest of lymph nodes after colonic resection.
abstract: OBJECTIVE
  To find out if clearance of surgical colectomy specimens with xylene gave a higher yield of lymph nodes and more accurate staging than the traditional step-sectioning technique.
  
  
  METHODS
  Consecutive open study.
  
  
  METHODS
  Private hospital, United States.
  
  
  METHODS
  84 specimens from colonic resections, 4 of which were total colectomies and the remaining 80 segmental resections.
  
  
  METHODS
  The first 41 (2 colectomies and 39 segmental resections) were cleared by step-sectioning alone (to establish baseline values). The remainder (n = 2 and 41, respectively) were step-sectioned, the lymph nodes were removed, and then the residual tissue was cleared with xylene.
  
  
  METHODS
  The number of lymph nodes found, and if the diagnosis was changed by the finding of additional nodes.
  
  
  RESULTS
  The baseline values in the two total colectomy specimens were 76 and 101, and the mean (range) after segmental colectomy was 21 (1-98). The values after total colectomy in the second group were 33 and 73, and after xylene clearance an additional 12 and 17 nodes were found. After segmental colectomy a mean (range) of 13 (0-43) was found, and an additional 4 (0-12) were found after xylene clearance. No additional nodes containing metastases were found in total colectomy specimens after xylene clearance, and only 6 additional nodes after segmental resection contained metastases. These changed the histological stage of the disease in only 2 patients.
  
  
  CONCLUSIONS
  Xylene clearance offers little advantage over careful traditional step-sectioning of specimens, but may be of value if the histopathologist does not do routine meticulous step-sectioning.
authors.affiliation: Department of Colorectal Surgery, Cleveland Clinic Florida, Ft. Lauderdale.
authors.forename: S M
authors.initials: SM
authors.lastname: Cohen
authors.forename: S D
authors.initials: SD
authors.lastname: Wexner
authors.forename: S L
authors.initials: SL
authors.lastname: Schmitt
authors.forename: J J
authors.initials: JJ
authors.lastname: Nogueras
authors.forename: F V
authors.initials: FV
authors.lastname: Lucas
mesh_terms: D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D016591:Histocytological Preparation Techniques; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008643:Mesentery / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D011446:Prospective Studies; D014992:Xylenes
chemical_list: D014992:Xylenes