Vertical and horizontal growth features of superficial esophageal squamous cell carcinomas: histopathological evaluation of endoscopically resected specimens

Endoscopic mucosal resection (EMR) has been performed for intramucosal carcinomas with excellent results. To evaluate invasion depth of superficial esophageal squamous cell carcinomas (SESCCs) accurately, it is important to elucidate vertical and horizontal growth features. Using 179 specimens of SESCC taken by EMR, various factors associated with vertical and horizontal growth were examined pathologically to determine which were correlated with invasion depth, classified for this purpose into four levels, m1, m2, m3, and sm. Maximum tumor diameter, including high-grade intraepithelial neoplasia, differed between m1 and m2 cases and for invasive lesions between m2 and m3. Maximum tumor thickness varied between m1 and m2, m2 and m3, and m3 and sm. Multivariate analysis showed tumor thickness and diameter of invasion to be correlated with submucosal invasion. Tumor thickness and depth of the depressed lesions were correlated in depressed/flat type cases. In elevated type cases the thickness of the tumor did not differentiate between m3 and sm. Shape of the elevated lesion also influenced the invasion depth. Frequency of infiltrating type tumors, composed of irregular and small invading nests, was higher with sm than m3. To differentiate m3 and sm tumor the classification of gross type, thickness, depth of depressed lesions, shape of elevated lesions, and invasion patterns should all be evaluated.