Solid Pseudopapillary Tumor : Infiltration
Microscopic Features of Solid Pseudopapillary Tumor (SPT) of Pancreas: The image shows microscopic areas of delicate infiltration into the surrounding non-neoplastic pancreas. Although most tumors are grossly well-demarcated, neoplastic cells can focally infiltrate into the surrounding pancreatic tissue, entrapping acinar cells and islets. Vascular and perineural invasion is rare. There are no pathologic criteria that can reliably predict high risk for aggressive behavior; however, perineural invasion, angioinvasion, deep infiltration of the surrounding pancreas, significant nuclear atypia, and an unusually high mitotic rate have been associated with malignant behavior.