037). Mean score for the degrees of cytological

abnormalities of LGD component was similar to that of tumor invasive front (P = 0.457) and significantly higher than that of small LGD lesions (P < 0.001). Conclusion:  Our results indicate the possibility that the lesion was formed by a combination of small lesions that arose as a multicentric occurrence of squamous cell carcinoma and dysplasia. Our results also suggest that an LGD component would transform to carcinoma along with tumor progression. However, the concept of ‘basal cell layer type carcinoma in situ’ may be suitable for squamous cell selleck screening library lesions with a high degree of cytological abnormalities confined to the lower half of the epithelium. The development in recent years of techniques for endoscopic diagnosis have led to the detection of increasing numbers of early-stage esophageal squamous cell carcinoma (SCC).1–3 Many such lesions can be treated by endoscopic mucosal resection (EMR) with minimal invasiveness.4–7 The ability to detect early squamous neoplasia of the esophagus can be enhanced considerably by iodine staining during endoscopic

examination.1–3 Early esophageal carcinoma is usually observed as an iodine-unstained area. However, biopsy specimens obtained from the iodine-unstained lesion detected in endoscopic examination are often histologically diagnosed as low-grade dysplasia. In the World Health Organization (WHO) classification of tumors of the digestive system, intraepithelial neoplasia in squamous epithelium of the esophagus is graded as low-grade dysplasia when KU-60019 ic50 both architectural and cytological abnormalities are confined to the lower Erythromycin half of the epithelium.8 This nomenclature is

the same as the categories of the Vienna classification of gastrointestinal epithelial neoplasia, category 3 being non-invasive low-grade neoplasia, and follow up without treatment is recommended for such lesions.9,10 There are very few reports on the characteristics of such intraepithelial squamous lesions, and it has not been determined whether such lesions are pre-cancerous lesions or not and whether such lesions have malignant potential or not. To clarify the characteristics of low-grade dysplasia, prospective follow-up study for such lesions is important, and histological study for early invasive SCC may also be important. If low-grade dysplasia progresses to high-grade intraepithelial neoplasia and SCC, early esophageal carcinoma lesions that have such a natural history (the so-called dysplasia–carcinoma sequence) might contain a remaining low-grade dysplasia component. The purpose of this study was to investigate the low-grade dysplasia component in early invasive SCC of the esophagus and to clarify the clinical significance of low-grade dysplasia.