Abstract
Abdominal ultrasound revealed a liver tumor in a 46-year-old male during a medical screening, and a hemangioma on contrast-enhanced tomography （CT）and, a pancreatic mass were also found. The patient was then referred to our department for further evaluation and treatment. A 2cm tumor with massive central calcification was observed in the pancreatic tail. Although the contrast enhancement was poor in the arterial phase, the contrast enhancement was equal to that of the surrounding pancreatic tissue in the equilibrium phase. A low signal was displayed on T1-weighted magnetic resonance imaging （MRI），whereas a mildly elevated signal was displayed on T2-weighted MRI. During endoscopic ultrasonography（EUS），the tumor was visualized as a well-defined hypoechoic lesion with central calcification. Considering the above imaging findings, the differential diagnoses of solid pseudopapillary neoplasm（SPN）and neuroendocrine tumor were proposed. We performed endoscopic ultrasound-guided fine-needle aspiration（EUS-FNA）to obtain a definitive diagnosis. Hyperplasia of the tumor cells with small oval nuclei was observed upon histopathological examination. Immunostaining revealed that the tumor was positive for vimentin, CD 10 and β-catenin and negative for chromogranin A. SPN was suspected based on this immunostaining pattern. We performed laparoscopic spleen-preserving resection of the pancreatic body and tail. SPN was ultimately diagnosed during the histopathological examination of the resected specimen.
