ABSTRACT
Objective To analyze the application of clinicopathological features and LEF-1 in the diagnosis of solid pseudopapillary neoplasm of the pancreas (SPN).Methods Clinical and pathological data of 227 cases who were pathologically diagnosed as pancreatic SPN at Changhai Hospital from Jan 2000 to Dec 2015 were collected and analyzed.Immunochemical assay was used to detect the expression of LEF-1 in 132 cases of SPN, and the results were compared with β-catenin, which is most commonly used for diagnosing SPN.Results 81.9% of patients with SPN were female (186/227).Mean age at the onset was 34 years.Mean tumor size was 5.4 cm.48.5% tumors were localized in the pancreatic tail, and 33% in the head.46.3% tumors were cystic and solid, 42.3% were solid, and 11.4% were cystic.There were 2 cases of lymph node metastasis (0.9%), 15 cases of vascular tumor thrombus (6.6%), 14 cases of nerve invasion (6.2%), and 13 cases of adjacent organs invasion (5.7%) based on microscopic observations.Immunochemical analysis showed that 130 of 132 cases with SPN expressed LEF-1 with strong nuclear positivity, and the positivity rate was 98.5%.But no obvious expression of LEF-1 can be seen in normal pancreatic tissue and other pancreatic tumors.The specificity was 100%.The positivity of β-catenin expression in SPN was 96.6%(144/149), and β-catenin was positively expressed in only one case of acinar cell carcinoma.Tumors were completely removed by surgery in 165 cases, and the median follow-up was 51 months.By Oct 31, 2016, 162 patients (98.2%) survived, 5 had liver metastasis, and 1 had recurrence.Conclusions SPN is predominantly encountered in young female patients, and the clinical manifestations are not specific.LEF-1 can be used as a specific marker for the diagnosis and differentiation of SPN, which is more accurate than β-catenin.