title: Differentiation between benign and malignant solid pseudopapillary tumor of the pancreas by MDCT.
abstract: OBJECTIVE
  The purpose of this study was to determine if characteristic features on computed tomographic and (or) magnetic resonance imaging can differentiate benign and malignant solid pseudopapillary neoplasms (SPN).
  
  
  METHODS
  A total of 82 pathologically diagnosed SPN patients were included. CT and MRI were reviewed by 3 radiologists. Each tumor was analyzed through the clinical and imaging features.
  
  
  RESULTS
  The highest occurrence of malignant SPN was observed in the group of patients (11-19 years old) followed by the group of patients (50-65 years old). When the tumor was located in the tail and the size was equal or larger than 6.0 cm, the positive and predictive value, the predictive value, sensitivity and specificity for a malignant SPN were 61.5%, 100%, 100% and 78.6%, respectively. Presence of complete encapsulation was more frequent in benign SPNs, but focal discontinuity in the malignant SPNs. Amorphous or scattered calcifications, all near-solid tumors and presence of upstream pancreatic ductal was found in the benign SPNs.
  
  
  CONCLUSIONS
  A focal discontinuity of the capsule, large tumor size (>6.0 cm) and a pancreatic tail location may suggest malignancy of SPN. In contrast, tumors with amorphous or scattered calcifications, and all near-solid tumors may be indicative of benignancy. Age (less than 20 or more than 50 years old) is a possible risk factor of SPN. In comparison to other pancreatic neoplasms, such as ductal adenocarcinoma, a complete/incomplete pseudo-capsule, without upstream pancreatic duct dilatation and lymph nodes metastasis, and the presence of internal calcification and hemorrhage are more likely SPN.
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No.197, Ruijin 2nd Road, Shanghai 200025, China. yinqihuaphd@163.com
authors.forename: Qihua
authors.initials: Q
authors.lastname: Yin
authors.forename: Mingliang
authors.initials: M
authors.lastname: Wang
authors.forename: Chengsheng
authors.initials: C
authors.lastname: Wang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Wu
authors.forename: Fei
authors.initials: F
authors.lastname: Yuan
authors.forename: Kun
authors.initials: K
authors.lastname: Chen
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Tang
authors.forename: Xuesong
authors.initials: X
authors.lastname: Zhao
authors.forename: Fei
authors.initials: F
authors.lastname: Miao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging*; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult