title: Morphological features of early gallbladder carcinoma.
abstract: OBJECTIVE
  This study aimed to clarify the morphological features of early gallbladder carcinoma including tumors invading the lamina propria (pT1a) or muscular layer (pT1b).
  
  
  METHODS
  This retrospective study involved 299 patients with early gallbladder carcinomas, identified from a surgical pathology database covering 29 years from 1982 through 2010. The macroscopic appearance of the tumor was classified as protruding (n=107, 36%) or superficial (n=192, 64%). Protruding tumors were subdivided into pedunculated or sessile, whereas superficial tumors were subdivided into elevated, flat or depressed.
  
  
  RESULTS
  Eighty-four of 107 protruding tumors (79%) were detected preoperatively and/or intraoperatively, whereas only 47 of 192 superficial tumors (24%) were detected in this manner (p<0.001). Of the 107 protruding tumors, 21 were pedunculated and 86 were sessile; 76 of these sessile tumors (88%) were accompanied by superficial elevated and/or flat tumors. In total, 257 patients (86%) had pT1a tumors and 42 (14%) had pT1b tumors. No patient had evidence of lymphatic/blood vessel or perineural invasion or nodal metastasis on histology, except for lymphatic vessel invasion in one patient with a pT1b tumor.
  
  
  CONCLUSIONS
  Two-thirds of early gallbladder carcinomas are classified as superficial. Most pT1b gallbladder carcinomas spread only locally.
authors.affiliation: Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Wakai
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ajioka
authors.forename: Naoto
authors.initials: N
authors.lastname: Nagino
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shirai
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Hatakeyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005706:Gallbladder Neoplasms / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012189:Retrospective Studies