title: Low-grade dysplasia component in early invasive squamous cell carcinoma of the esophagus.
abstract: OBJECTIVE
  It has not been determined whether low-grade squamous dysplasia (LGD) of the esophagus is a precancerous lesion or not. If LGD progresses to squamous cell carcinoma, early carcinoma lesions that have such a natural history might contain a remaining LGD component.
  
  
  METHODS
  The lesions in the 68 patients with early invasive squamous cell carcinoma who underwent endoscopic mucosal resection were examined for the presence of an LGD component. If LGD components were observed, the degrees of architectural and cytological abnormalities of LGD components and those of tumor invasive fronts in the same lesions were studied. The degrees of abnormalities of 28 small LGD lesions were also studied.
  
  
  RESULTS
  Histological examination of resected specimens confirmed LGD components in 43% of the squamous cell carcinoma lesions. The lesions of lamina propria mucosae (m2) cancer contained a significantly broader area of LGD component than did the lesions of muscularis mucosae (m3) and submucosal layer (sm) cancer (P = 0.037). Mean score for the degrees of cytological abnormalities of LGD component was similar to that of tumor invasive front (P = 0.457) and significantly higher than that of small LGD lesions (P < 0.001).
  
  
  CONCLUSIONS
  Our results indicate the possibility that the lesion was formed by a combination of small lesions that arose as a multicentric occurrence of squamous cell carcinoma and dysplasia. Our results also suggest that an LGD component would transform to carcinoma along with tumor progression. However, the concept of 'basal cell layer type carcinoma in situ' may be suitable for squamous cell lesions with a high degree of cytological abnormalities confined to the lower half of the epithelium.
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. yshimizu@med.hokudai.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Kato
authors.forename: Jojo
authors.initials: J
authors.lastname: Hirota
authors.forename: Shouko
authors.initials: S
authors.lastname: Ono
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kanako
authors.initials: K
authors.lastname: Kubota
authors.forename: Masahiro
authors.initials: M
authors.lastname: Asaka
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002278:Carcinoma in Situ / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D018450:Disease Progression; D004938:Esophageal Neoplasms / Q000473:pathology*; D004945:Esophagoscopy; D004947:Esophagus / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011230:Precancerous Conditions / Q000473:pathology*