Shogo Honda, Hiroshi Yamaguchi, Eriko Aimono, Shigeo Hara, Sachiko Minamiguchi, Tomoko Norose, Nobuyuki Ohike, Toshiko Yamochi, Masanori Yasuda, Takuya Moriya, Yuki Shiko, Hiroshi Nishihara, Toshitaka Nagao
Pancreatic solid pseudopapillary neoplasm (SPN) is a low-grade malignant neoplasm with a good prognosis. Clinically aggressive SPNs have rarely been reported but have not been analyzed in detail. In this study, we referred to this highly malignant type of SPN as high-grade SPN (HG-SPN) and compared its clinicopathological and genetic characteristics with conventional SPN (C-SPN) using immunohistochemistry and gene panel analyses. Five HG-SPNs and 15 C-SPNs were evaluated in this study. HG-SPNs share many pathologic characteristics: macroscopically, solid/cystic appearances, microscopically, pseudopapillary/pseudorosette pattern (100%), tumor cell loose cohesiveness (100%), thin/delicate vasculature (100%), tumor cell cytoplasmic vacuolization (100%), immunohistochemical positivity for β-catenin (nuclear expression) (100%), CD10 (80%), CD56 (80%), and vimentin (100%)...
March 1, 2024: American Journal of Surgical Pathology