title: [CT differential diagnosis of cystic nephroma and multilocular cystic renal cell carcinoma].
abstract: OBJECTIVE
  To study the CT findings of cystic nephroma (CN) and multilocular cystic renal cell carcinoma (MCRCC) and to improve the accuracy of preoperative diagnosis of these two diseases.
  
  
  METHODS
  The CT findings of nine CN cases and 19 MCRCC cases confirmed by pathology were blindly reviewed and compared with their pathological results. Fisher's exact test and independent-samples T test were applied to statistically analyze some of the CT features of the CN and MCRCC lesions.
  
  
  RESULTS
  The thickness of cystic walls and partitions in the nine CN cases ranged from 0.5 to 5 mm. Cystic walls and partitions were slightly thicker in some parts without visible mural nodules. Varying amounts of solid tissue could be found in all the 19 MCRCC tumors, and the cystic walls and partitions were found partially thickened ranging from 3 mm to 13 mm. Eight cases were with mural nodules (nodule diameter: 4.5-16 mm). Nine cases of CN tumors were lobulated and 7 protruded into the renal sinus. Three out of the 19 MCRCC presented shallow lobulation, and 7 tumors protruded into the renal sinus. The CT contrast-enhancement scanning displayed moderate delayed enhancement in the cystic walls and partitions in 8 cases. The enhanced scanning revealed that all the nine cases showed enhancement of the cystic walls and partitions, while 8 cases of them had mild to moderate delayed enhancement. The cystic walls, partitions and nodules were enhanced in 19 MRCC cases, among them 17 cases displayed obvious enhancement in the cortical phase. Among the differences of CT findings between MC and MRCC, the shallow lobulation, protruding into the renal sinus, mural nodules, cystic wall and partition thickness, and net growth in the cortical and nephrographic phase were statistically significantly different (P<0.05 for all).
  
  
  CONCLUSIONS
  CT scan can provide significant evidence for CN and MCRCC diagnosis. CN cases usually present relatively thin and even cystic walls and partitions without mural nodules and with shallow lobulation and protruding into the renal sinus. The enhancement is mild to moderate, dynamic and delayed, while the opposite CT findings may indicate a higher possibility of MCRCC.
authors.affiliation: Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China.
authors.forename: Jinkun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Email: rjk_zhao@163.com.
authors.forename: Zhaoxiang
authors.initials: Z
authors.lastname: Ye
authors.forename: Renju
authors.initials: R
authors.lastname: Bai
authors.forename: Xusheng
authors.initials: X
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Pan
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000000981:diagnostic imaging*; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed