[Clinicopathologic features of cases with negative pathologic results after endoscopic submucosal dissection].

Endoscopic submucosal dissection (ESD) is accepted as a standard treatment of early gastric cancer (EGC) and gastric adenoma. Occasionally, tumorous lesion is not found and pathologic discrepancies can occur after ESD. The aim of this study was to analyze the factors affecting the negative pathologic results after ESD. We retrospectively reviewed the data from all patients with gastric neoplasm (276 EGC and 516 gastric adenomas) who were treated with ESD during past 3 years and enrolled the patients who had negative pathologic results. Out of 792 patients treated with ESD, 27 patients (3.4%) were eligible for inclusion. Among the 27 patients, factors affecting the negative pathologic results were, most commonly, the focal lesion (n=13, 48.2%) which was small enough to be removed completely during pre-ESD biopsy, followed by pathologic discrepancies (n=11, 40.7%) between pathologists and lastly the operator factor (n=3, 11.1%) dissecting incorrect lesions. Of the focal lesions, the initial pathologic diagnoses were adenocarcinoma in 11 cases (84.6%). In cases with pathologic discrepancies, all the pretreatment diagnoses were adenoma with low grade dysplasia. In cases caused by operator factors, intestinal metaplasia was accompanied by elevated adenoma in all cases. To decrease negative pathologic results after ESD, an endoscopist should perform ESD after sufficient communication with pathologists, especially for adenoma with low grade dysplasia, and choose correct lesion, especially located at the antrum and associated with intestinal metaplasia. The possibility of total removal of small lesions even by forcep biopsy should be considered.