Brief Article
Copyright ©2010 Baishideng. All rights reserved.
World J Gastroenterol. Feb 28, 2010; 16(8): 1025-1030
Published online Feb 28, 2010. doi: 10.3748/wjg.v16.i8.1025
Pathological differential diagnosis of solid-pseudopapillary neoplasm and endocrine tumors of the pancreas
Bao-An Liu, Zhuo-Ming Li, Zhan-San Su, Xiao-Ling She
Bao-An Liu, Zhuo-Ming Li, Department of Pathology, Xiangya Basic Medical School, Central-south University, Changsha 410013, Hunan Province, China
Zhan-San Su, Department of Pathology, Xiangya Third Hospital, Central-south University, Changsha 410013, Hunan Province, China
Xiao-Ling She, Department of Pathology, Xiangya Second Hospital, Central-south University, Changsha 410006, Hunan Province, China
Author contributions: Li ZM performed the majority of experiments and wrote the manuscript; Liu BA was involved in editing the manuscript and provided financial support; Su ZS reviewed all pathological slides; She XL participated in some experiments.
Supported by Department of Pathology, Xiangya Basic Medical School, Central-south University
Correspondence to: Bao-An Liu, Professor, Department of Pathology, Xiangya Basic Medical School, Central-south University, 110# Tongzipo Road, Changsha 410013, Hunan Province, China. lba118@yahoo.com.cn
Telephone: +86-731-82651410 Fax: +86-731-82651410
Received: November 6, 2009
Revised: December 31, 2009
Accepted: January 7, 2010
Published online: February 28, 2010
Abstract

AIM: To investigate differential points of solid-pseudopapillary neoplasm (SPN) of the pancreas and pancreatic endocrine tumor (PET).

METHODS: Ten cases of SPN and fourteen cases of PET were studied in this retrospective study. Clinical and pathologic features, immunostaining reactions and β-catenin gene mutations were analyzed.

RESULTS: The mean age of SPN patients was 25.6 years and these patients had no specific symptoms. The mean diameter of the tumors was 11.0 cm, 9/10 cases were cystic or a mixture of solid and cystic structures, and there was hemorrhage and necrosis on the cut surface in 8/10 (80%) cases. Characteristic pseudopapillary structure and discohesive appearance of the neoplastic cells were observed in all 10 (100%) cases. The results of immunostaining showed that nuclear expression of β-catenin and loss of E-cadherin in all the cases, was only seen in SPN. Molecular studies discovered that 9/10 (90%) cases harbored a point mutation of exon 3 in β-catenin gene. On the other hand, the mean age of PET patients was 43.1 years. Eight of 14 cases presented with symptoms caused by hypoglycemia, and the other 6 cases presented with symptoms similar to those of SPN. The mean size of the tumors was 2.9 cm, most of the tumors were solid, only 3/14 (21%) were a mixture of solid and cystic structures, and macroscopic hemorrhage and necrosis were much less common (3/14, 21%). Histologically, tumor cells were arranged in trabecular, acinar or solid patterns and demonstrated no pseudopapillary structure and discohesive appearance in all 14 (100%) cases. The results of immunostaining and mutation detection were completely different with SPN that membrane and cytoplastic expression of β-catenin without loss of E-cadherin, as well as no mutation in β-catenin gene in all the cases.

CONCLUSION: Both macroscopic and microscopic features of SPN are quite characteristic. It is not difficult to distinguish it from PET. If necessary, immunostaining of β-catenin and E-cadherin is quite helpful to make the differential diagnosis.

Keywords: Solid-pseudopapillary neoplasm of the pancreas, Pancreatic endocrine tumor, Immunohistochemistry, β-catenin gene, Differential diagnosis