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Clinicopathological features of undifferentiated mixed type early gastric cancer treated with endoscopic submucosal dissection.

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.