Solid pseudopapillary tumor of the pancreas (SPPT). Still an unsolved enigma

Solid pseudo-papillary tumor (SPPT) is a rare cystic tumor of the pancreas (1-3% of exocrine tumors of the pancreas) which shows an "enigmatic" behavior on the clinical and molecular pattern. A retrospective analysis of the cytological studies and resected specimens of pancreatic cystic tumors from May 1996 to February 2010 was carried out. Three cases of SPPT were found, which are the objective of this study. The diagnosis was established upon occasional finding in the abdominal CT, in spite of sizing between 3 and 6 cm of diameter. In the three cases the preoperative diagnosis was confirmed by cytology and specific immunohistochemical staining. Cases 2 and 3 showed strong immunoreactivity for Beta-Catenin and E-Cadherin staining. Radical resection (R0) was carried out in the three cases. A young male -21 years of age (case 1)- who had duodenal infiltration and two lymph nodes metastases died of hepatic and peritoneal recurrence 20 months following surgery. The other two cases are free of disease. The current review of the literature reports roughly 800 cases since the first report in 1959, and shows the enigmatic character of this tumor regarding the cellular origin, molecular pathways, prognostic factors and clinical behavior.