Background/aims: Previous published data on the differentiated/undifferentiated mixed-type early gastric cancer treated with ESD are scarce.
Methodology: 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.
Conclusion: 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.