Solid-Pseudopapillary neoplasm of the pancreas: A clinicopathological review of 20 cases including rare examples.

AIMS: Solid-pseudopapillary neoplasm (SPN) is an uncommon malignant tumor of the pancreas with a favorable prognosis unlike other pancreatic neoplasms. We investigated the clinicopathological features of 20 patients with SPN in details. METHODS: The patients diagnosed as SPN in Dokuz Eylul University Hospital between January 2005 and March 2016 were reviewed in terms of clinical and histopathological data. RESULTS: Mean age of the patients was 33. Three of our cases were male and 4 were children. Some patients had synchronuous malignancies. Nine patients were diagnosed by fine needle aspiration cytology (FNAC). One of our tumors had 2×1mm of pancreas endocrine neoplasm in addition to SPN. One case had foci of atypical and multinucleated giant cells. All cases were positive for vimentin and CD10 antibodies and most were positive for PR and ß-catenin. The mean follow-up duration was 40 mo (range 2-110 mo). Only one case showed liver metastasis. CONCLUSION: Herein we present a series of 20 patients with 3 male and 4 pediatric cases, almost half of which were diagnosed with FNAC findings, and most of which are clinically being followed with one patient showing progression. Our series includes rare examples like collision tumor of SPN and pancreas endocrine neoplasm, SPN with multinucleated giant cells. Also cases with no surgical treatment and no progression, as well as cases with synchronous malignancies are presented. We believe that FNAC findings of any pancreatic mass should be investigated in detail for the designation of a therapy plan especially for the patients with high operation risks. The findings in our series also show that extensive necrosis, angioinvasion, perineurial invasion and larger tumor size might be predictive for worse prognosis and these patients should be more closely followed up.