title: [Diagnosis and treatment of multilocular cystic renal cell carcinoma: a study of 22 cases].
abstract: OBJECTIVE
  To summarize the diagnosis and treatment of multilocular cystic renal cell carcinoma (MCRCC), a special subtype of renal cell carcinoma.
  
  
  METHODS
  The clinical data of 22 cases of MCRCC diagnosed and treated from January 1998 to December 2002 in the First Hospital of Peking University were analyzed retrospectively.
  
  
  RESULTS
  482 patients with renal cell carcinomas were hospitalized during that period with a male-to-female ratio of 2.09:1. Out of the 482 cases 22 cases (4.56%) were classified as MCRCC with a male-to-female ratio of 2.67:1, not significantly different from that of the general group of renal cell carcinoma patients (P > 0.05). The mean age of the patients of MCRCC was 46.6 years, significantly lower than that of the patients with other types of renal cell carcinomas (57.83 years, P< 0.01). Eighteen cases were diagnosed correctly as renal carcinomas before operation. Six patients (27%) were at the stage pT(1)N(0)M(0), 15 (68%) at the stage pT(2)N(0)M(0), and 1 (5%) at the stage pT(3)bN(0)M(0). The classification according to the tumor nuclear grading system showed 5 carcinomas (23%) of tumor nuclear grade 1, 17(77%) are of tumor nuclear grade 2. Eighteen patients underwent radical renal nephrectomy and 4 underwent partial nephrectomy.
  
  
  CONCLUSIONS
  The preoperative diagnosis of MCRCC, difficult to be differentiated from other cystic renal diseases, mainly depends on imaging studies. Intraoperative frozen-section or nephron sparing surgery will benefit the patients if the preoperative diagnosis is unclear, especially for the patients of category 3 or 4 of Bosniak's system.
authors.affiliation: Department of Urology, The First Hospital of Peking University, Institute of Urology, Peking University, Beijing 100034, China.
authors.forename: Kan
authors.initials: K
authors.lastname: Gong
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Yan-qun
authors.initials: YQ
authors.lastname: Na
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D052177:Kidney Diseases, Cystic / Q000175:diagnosis* / Q000601:surgery; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012737:Sex Factors; D014057:Tomography, X-Ray Computed