Differentiation of Small Colorectal Lesions; Laser-Induced Autofluorescence Using the Wavstat

However, limited data are available on the validity of endocytoscopy in the diagnosis of gastric disorders. The aim of this prospective study was to evaluate the feasibility of endocytoscopy in the diagnosis of early gastric cancer. Methods: Patients who planned to undergo magnifying endoscopic work-up before or after gastric ESD were eligible. Examination was done with a single CCD integrated endocytoscope. Patients who had gastric lesions that required histopathological diagnosis with biopsy specimen were enrolled and evaluated by endocytoscopy with a double staining of 0.05% crystal violet and 0.1% methylene blue. Endocytoscopic atypia of gland structure was assessed. Structural atypia was defined by the presence of three morphological abnormalities; absence or narrowing of inter-glandular space, glandular fusion and glandular destruction. Endocytoscopic atypia were graded as none, low and high. The primary endpoint was the accuracy of endocytoscopic diagnosis for gastric cancer using histopathological diagnosis of biopsy specimens as the gold standard. Results: 1) Eighty-two lesions in 54 patients were enrolled; 23 early gastric cancers (21 well differentiated type, 2 poorly differentiated type), 10 gastric adenomas, 10 gastric ulcers, 10 gastric erosions, 18 gastric protruded lesions. Eleven points of gastric mucosa surrounding gastric neoplasia were also examined to evaluate neoplasia extent for precise endoscopic resection. 2) Ten lesions could not be well observed by endocytoscopy because of poor staining due to viscous mucus or dense ulcer plaque. The assessable rates with endocytoscopy were 88% (72/ 82) in total and 91% (21/23) in gastric cancer, whereas it was 78% in gastric protruded lesions, especially was low at 50% in hyperplastic polyps.3) High grade of endocytoscopic atypia was observed in 86% of assessable gastric cancers (n 21), whereas high grade of endocytoscopic atypia was not observed in assessable lesions of gastric adenomas and other nonneoplastic lesions. Low grade of endocytoscopic atypia was observed in 78% of assessable gastric adenomas (n 9), 9% of gastric cancer, and 2.3% of nonneoplastic lesions. Using the criterion of high grade-endocytoscopic atypia, sensitivity, specificity, PPV and NPV of endocytoscopic diagnosis for gastric cancer were 86%, 100%, 100% and 94%, respectively. 4) No serious complication occurred during and after the examinations. Conclusion: Endocytoscopy is a clinically feasible modality to obtain in vivo histology with high diagnostic accuracy in gastric cancer.