Current status and limitations of the newly developed endocytoscope GIF-Y0002 with reference to its diagnostic performance for common esophageal lesions.

Objectives: To investigate both neoplastic and non-neoplastic lesions of the esophagus and to clarify the features of the surface cell morphology using a newly developed endocytoscope, the GIF-Y0002. Methods: The surface cell morphology was examined with toluidine blue staining, and histological features of 53 patients with 54 lesions, including 39 patients with esophageal squamous cell carcinoma (ESCC) and 14 patients with 15 non-neoplastic esophageal lesions, were compared. One endoscopist classified the lesions using type classification, and we consulted one pathologist to evaluate the endocytoscopy pictures with regard to neoplasia or non-neoplasia. Results: The overall sensitivity for ESCC of the findings by the endoscopist and pathologist based on GIF-Y0002 observation were 100.0% and 94.9%, respectively; while the specificity was 80.0% and 46.7%. For the 3 cases of low-grade intraepithelial neoplasia, 2 were diagnosed as Type 2 and one case as suspected neoplasia by the endoscopist while the pathologist considered 2 cases to be neoplastic. Among the 9 cases of esophagitis, the endoscopist diagnosed 2 cases as Type 2 or 3, which was suggestive of neoplasia, whereas the pathologist diagnosed 6 cases to be neoplastic. Conclusion: The low percentage of specificity for the pathologist's diagnosis was considered to be attributed to the low magnification power of the GIF-Y0002. A further increase in the magnifying power of this instrument will be necessary to broaden its clinical applications.