title: Detection of venous invasion in surgical specimens of colorectal carcinoma: the efficacy of various types of tissue blocks.
abstract: BACKGROUND
  Venous invasion (VI) is an important prognosis predictor after colorectal carcinoma (CRC) resection, enabling more accurate staging and influencing postoperative management.
  
  
  OBJECTIVE
  To assess/compare various tissue block types (perpendicular, tangential, across mesentery (AM), from major vessels or lymph nodes (LNs)) for VI detection in CRC.
  
  
  METHODS
  Fifty two CRCs (51 colectomies, one polypectomy) were studied. Tumours were measured, surface area calculated, and colorectum and bowel wall sites recorded. Weigert's staining for elastin facilitated VI detection. VI sites, type, and amount were recorded. Ratios of relative yield of tissue block types to their frequency were calculated.
  
  
  RESULTS
  Average numbers of tissue blocks/colectomy specimen were: perpendicular, 10.2; tangential, 9.1; AM, 3.3; from major vessels, 2.1. Average number of LNs examined was 16.47. VI was detected in 22 tumours. Overall, VI was detected in 16 perpendicular, seven tangential, five AM, and two LN blocks. VI was detected in eight, two, one, and three tumours in perpendicular, tangential, LN, and AM blocks alone, respectively. In seven tumours, VI was identified in multiple tissue block types. The average number of blocks obtained was 39.7, 42.1, and 38 from all tumours, VI positive, and VI negative tumours, respectively (p = 0.0497). Efficacy to detect VI was 2.151, 2.088, 1.092, 0.172, and 0 for AM, perpendicular, tangential, LN, and mesenteric vessel blocks, respectively.
  
  
  CONCLUSIONS
  VI was identified most frequently and in eight cases only in perpendicular blocks. However, extramural VI was detected in six tumours only in blocks cut tangentially, AM, or from harvested LNs. Hence, all these types of blocks should be submitted routinely and scanned for VI.
authors.affiliation: Department of Surgery A, Hillel Yaffe Medical Centre, Hadera 38100, and the Rappaport Faculty of Medicine, the Technion, Haifa, Israel. Sternberg_a@hillel-yaffe.health.gov.il
authors.forename: A
authors.initials: A
authors.lastname: Sternberg
authors.forename: A
authors.initials: A
authors.lastname: Mizrahi
authors.forename: M
authors.initials: M
authors.lastname: Amar
authors.forename: G
authors.initials: G
authors.lastname: Groisman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001808:Blood Vessels / Q000473:pathology*; D003082:Colectomy; D003106:Colon / Q000098:blood supply; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012007:Rectum / Q000098:blood supply; D013048:Specimen Handling / Q000379:methods