Solid pseudopaillary neoplasm of the pancreas: analysis of clinicopathological and immunohistochemical features in 10 cases.

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the clinicopathological features and immunomarkers of Solid Pseudopapillary Neoplasm of the Pancreas (SPN) and to find the best possible immunomarker combination that can accurately diagnose it. METHODS: We retrospectively analyzed 10 patients who underwent surgery for pathologically confirmed SPN from August 2013 to August 2017. Follow-up of the patients was between 9 and 57 months. RESULTS: Clinical symptoms and imaging were atypical. In general, the mass was encapsulated and clearly defined by the surrounding tissues. Cut surface was dusty-red and associated with hemorrhage. The neoplastic cell cytoplasm was eosinophilic or clear, and the nuclei were round or oval, presenting typical features of pseudopapillary distribution around a fibrovascular core. Immunohistochemical results showed that tumor cells were consistently positive for vimentin, CD56, CD10, PR, CD99, ß-catenin and negative for E-cadherin (100%) and chromogranin. CD99 presented a unique dot-like staining pattern in tumor cells. CONCLUSIONS: In view of the atypical clinical manifestations and imaging features of SPN, accurate diagnosis mainly relies on the histomorphology and immunomarker combination including PR, CD99, ß-catenin, and E-cadherin, which might be useful method in the diagnosis of SPN.