title: Comprehensive lymph node morphometry in rectal cancer using acetone compression.
abstract: OBJECTIVE
  Acetone compression (AC) is an elution compression technique for the comprehensive pathological examination of fatty tissue. Here AC is combined with digital morphometry to evaluate the impact of preoperative (neoadjuvant) chemoradiotherapy (neoCRT) on lymph node (LN) numbers and morphology in locally advanced rectal cancer. AC is compared with complete embedding of the mesorectal fat (whole mesorectal embedding (WME)) to exclude artificial alterations and to the standard technique, manual dissectioning (MD).
  
  
  METHODS
  320 rectal cancer specimens were subjected to LN morphometry. Neoadjuvant CRT was applied in 204 specimens. LNs were prepared either with AC (n=138), WME (n=51) or MD (n=131). 8523 LNs were assessed including 530 nodes with metastases.
  
  
  RESULTS
  LN prepared by AC and WME showed similar morphologies. AC revealed reduced LN sizes in neoCRT specimens compared with primary resection (2.2; 2.4 mm, p=0.049) while the LN number was comparable (27; 30/specimen). AC yielded 28 LN/specimen on average, MD yielded 22 LN (p<0.001). In neoCRT specimens, MD yielded less LN compared with primary resection (19; 25). MD detected less small LN (<2 mm; MD: 25%; AC: 56%) while 24 of the 135 LN metastases found by AC were ≤2 mm in diameter.
  
  
  CONCLUSIONS
  AC does not alter LN morphology and is especially suited to retrieve small LN after neoadjuvant CRT of rectal cancer. Neoadjuvant multimodality treatment caused reduced LN sizes while the LN numbers were not affected. When compared with MD, AC proved more reliable in the retrieval of LN from rectal cancer specimens after neoCRT.
authors.affiliation: Institute of Pathology, University Hospital Cologne, Cologne, Germany Department of Pathology, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Scheel
authors.affiliation: Department of Pathology, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Reineke
authors.affiliation: Department of General and Visceral Surgery, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Sprenger
authors.affiliation: Institute of Pathology Nordhessen, Kassel, Germany.
authors.forename: Suvi
authors.initials: S
authors.lastname: Lokka
authors.affiliation: Department of Pathology, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Kitz
authors.affiliation: Department of General and Visceral Surgery, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: B Michael
authors.initials: BM
authors.lastname: Ghadimi
authors.affiliation: Institute of Pathology Nordhessen, Kassel, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Rüschoff
authors.affiliation: Department of General and Visceral Surgery, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Liersch
authors.affiliation: Department of Pathology, University Medical Center Göttingen, Göttingen, Germany Institute of Pathology Nordhessen, Kassel, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Middel
mesh_terms: D000096:Acetone; D000368:Aged; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000473:pathology*; D012997:Solvents
chemical_list: D012997:Solvents; D000096:Acetone
keywords: LYMPH NODES; METASTASIS; RECTAL CANCER; SURGICAL PATHOLOGY