Matsueda K, et al. - Researchers evaluated the clinicopathological characteristics of SNADEN, including advanced carcinoma, focusing on tumor location by retrospectively collecting data from 410 patients clinically and pathologically diagnosed with SNADEN at 11 institutions in Japan from June 2002 to March 2014. On the oral side of the papilla of Vater (oral-Vater), the proportion of invasive carcinomas in SNADEN was significantly higher than on the anal side (anal-Vater). With oral-Vater, undifferentiated carcinoma was significantly more common than with anal-Vater. With oral-Vater, the recurrence rate of surgically R0 resected locally advanced carcinomas was significantly higher than anal-Vater. In addition, oral-Vater relapse-free survival was significantly shorter than anal-Vater survival. Overall, the investigators concluded that the oral-Vater clinicopathological characteristics of SNADEN differed from those of anal-Vater. Due to biologically higher malignancy, SNADEN on oral-Vater was more likely to be invasive carcinomas and could be more aggressive than on anal-Vater.