Endocytoscopic visualization of squamous cell islands within Barrett’s epithelium

Table 1 Revised Vienna classification of gastrointestinal epithelial neoplasia

Category	Diagnosis
Group 1	Negative for neoplasia
Group 2	Indefinite for neoplasia
Group 3	Mucosal low grade neoplasia
	Low grade adenoma
	Low grade dysplasia
Group 4	Mucosal high grade neoplasia
Subgroup 4.1	High grade adenoma/dysplasia
Subgroup 4.2	Non-invasive carcinoma (carcinoma in situ)
Subgroup 4.3	Suspicious for invasive carcinoma
Subgroup 4.4	Intramucosal carcinoma
Group 5	Submucosal invasion by carcinoma

The Endocytoscopic Atypia (ECA) Classification[10] for superficial esophageal squamous cell lesions is as follow: ECA 1: Large, cytoplasm-rich cells with a rhomboid shape are found in a regular arrangement. Small nuclei are located at their center. This appearance corresponds to healthy squamous epithelium in the esophagus; ECA 2: The cell margin often becomes round. Different-sized small nuclei are observed. The image often shows inflammatory or reactive changes; ECA 3: The cell becomes smaller in size but the nuclei are still compact. This appearance is often observed in borderline lesions; ECA 4: The number of cells increases with an increased nucleus-cytoplasm ratio. This appearance strongly suggests a malignant lesion; ECA 5: Cells of various sizes are arranged irregularly with a high nucleus-cytoplasm ratio. This appearance is recognized endoscopically as a definitely malignant lesion. All images were categorized according to size and uniformity of nuclei, number of cells and regularity of cellular arrangement. Higher ECA category is associated with stronger atypia. ECA 1 to ECA 3 corresponds to Vienna categories 1 to 3; ECA 4 to ECA 5 corresponds to Vienna categories 4 to 5. The data was quoted from the references of 13, 14.