title: Evaluation of CT findings for the differentiation of benign from malignant primary retroperitoneal tumors.
abstract: BACKGROUND
  Benign and malignant primary retroperitoneal tumors (RT) have different pathological manifestations, and overlapping imaging characteristics. This study aimed to evaluate the value of computed tomography (CT) for differentiating benign from malignant RT.
  
  
  METHODS
  One hundred and ninety-four patients with clinical and radiographic data were evaluated retrospectively following surgical resection of primary RT. There were 38.1% (n = 74) benign lesions and 61.9% (n = 120) malignant lesions. Categorical variables were tested with a chi-square test or Fisher's exact test for the diagnostic indexes and sensitivity and specificity of CT characteristics.
  
  
  RESULTS
  In univariate analysis, the differences in ill-defined margins, irregular surfaces, long diameter >6.75 cm, short diameter >6.25 cm, and solid or mixed texture had statistical significance; the sensitivity and specificity were 44.2% and 91.9%, 70.0% and 62.2%, 68.8% and 60.7%, 59.7% and 74.2%, 87.5% and 35.1%, respectively. In multivariate analysis, a combination of all the above indexes was the best model for differentiating malignant tumors, resulting in the most accurate diagnosis of malignancies with a sensitivity of 77.2% and a specificity of 81.1% (P < 0.0001) when the score was 4. The differences in other findings including CT attenuation, number, and calcification had no statistical significance. The unique characteristics included the spotted enhancement (mottled high density) in schwannoma (P < 0.0001), adipose tissue in liposarcoma (P < 0.0001) and paravertebral location in neurogenic tumors (P < 0.0001).
  
  
  CONCLUSIONS
  More accurate differential diagnosis of primary RT can be made through comprehensive analysis of the combined diagnostic indexes of CT. Some specific characteristics of CT can assist in preoperative planning.
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China. Email: xinmingzh@sina.com.
authors.forename: Xinming
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Jingrui
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Imaging Diagnosis, Cancer Institute & Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
authors.forename: Chunwu
authors.initials: C
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012186:Retroperitoneal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult