Serous cystic neoplasm in an intrapancreatic accessory spleen

Serous cystic neoplasm (SCN) of the pancreas is a benign epithelial neoplasm, except in extremely rare malignant cases. Development of SCN in tissues other than the pancreas has been never reported. Here we present the first reported case of SCN in an intrapancreatic accessory spleen (IPAS). A 54-year-old female patient with von Hippel-Lindau (VHL) syndrome was found to have pancreatic tail mass. Pathologically the 25-mm solid mass was an IPAS showing proliferation of clear cuboidal tumor cells without atypia, forming numerous small cysts. The tumor cells were rich in cytoplasmic glycogen and distributed in the splenic tissue almost diffusely. Immunohistochemically, tumor cells were positive for cytokeratins, MUC6, and neuron-specific enolase, and negative for neuroendocrine markers. From these findings, we diagnosed the lesion as SCN in IPAS. This tumor is suggested to develop as a VHL-associated SCN from coexisting pancreatic tissue in IPAS rather than as a metastatic tumor.