A series of 64 cases of pancreatic cystic neoplasia from an institutional study of China

Figure 4 Solid pseudo-papillary neoplasia. A: Cystic structures containing hemorrhagic debris surrounded by hemorrhagic-necrotic tissue; B: SPN showing solid areas consisting of monotonous polygonal epithelioid cells, often with minimal intervening stroma accompanied with innumerable capillary-sized vessels. In the pseudopapillary regions, the cells away from the small vessels appeared to have dropped away, leaving an irregular cuff of cells surrounding each vascular core (HE × 100); C: SPN showing a consistent pattern of reactivity for α-1-AT (Envison × 100); D: Positive β-catenin and progesteron receptor limited to the nuclei of tumor cells (Envison × 200).