title: Clinicopathological features of undifferentiated mixed type early gastric cancer treated with endoscopic submucosal dissection.
abstract: OBJECTIVE
  Previous published data on the differentiated/undifferentiated mixed-type early gastric cancer treated with ESD are scarce.
  
  
  METHODS
  The clinicopathological features of the pure differentiated type and differentiated/undifferentiated mixed type adenocarcinoma in final diagnosis of ESD specimens were investigated in 109 early gastric cancers patients treated with ESD.
  
  
  RESULTS
  Of the pure differentiated type (102 patients) and differentiated / undifferentiated mixed type (7 patients) adenocarcinoma, submucosal invasive tumors were detected in 6 (5.9%) and 4 cases (57.1%) (p = 0.017), respectively. The mean tumor size was 10.95 +/- 5.12mm and 22.85 +/- 9.51mm (p = 0.0091), respectively. In the cases diagnosed as moderately differentiated adenocarcinoma by preoperative ESD biopsy, submucosal invasive tumors were detected in 2 (12.5%) and 4 cases (57.1%) (p = 0.038), respectively, and the mean tumor size was 12.50 +/- 5.88mm and 22.85 +/- 9.51mm (p = 0.016), respectively. During a median follow-up period of 30.3 months (range: 7-52 months), there were no recurrences or metastasis in any of the 7 mixed type cases.
  
  
  CONCLUSIONS
  In conclusion, the results of our study suggest that large gastric tumors treated with ESD which are diagnosed as moderately differentiated adenocarcinoma in biopsy specimens potentially contain an undifferentiated component.
authors.affiliation: Department of Gastroenterology, Tokyo Medical University Ibaraki Medical Center, Japan. junnki@dg.mbn.or.jp
authors.forename: Junichi
authors.initials: J
authors.lastname: Iwamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mizokami
authors.forename: Masanori
authors.initials: M
authors.lastname: Ito
authors.forename: Koichi
authors.initials: K
authors.lastname: Shomokobe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hirayama
authors.forename: Akira
authors.initials: A
authors.lastname: Honda
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Saito
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ikegami
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Matsuzaki
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D004210:Dissection; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D005753:Gastric Mucosa; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome