title: Extensively cystic renal neoplasms in adults (Bosniak classification II or III)--possible "common" histological diagnoses: multilocular cystic renal cell carcinoma, cystic nephroma, and mixed epithelial and stromal tumor of the kidney.
abstract: OBJECTIVE
  To give an algorithm for resolution of extensively cystic renal neoplasms, preoperatively classified in the Bosniak classification as a category II and III.
  
  
  METHODS
  From 1991 to 6/2004, 701 patients with 727 renal tumours were surgically treated at our hospital. Extensively cystic tumours were found in 10 cases. Extensively cystic tumours were defined as multicystic tumours without any solid nodules visible neither on CT, nor grossly in the specimen at operation (the Bosniak classification type II or III).
  
  
  RESULTS
  Seven multilocular cystic renal cell carcinomas, three mixed epithelial and stromal tumour of the kidney and one cystic nephroma were diagnosed on histology.
  
  
  CONCLUSIONS
  Extensively cystic renal tumours classified as the Bosniak type II or III correspond histologically to the entities mentioned above (multilocular cystic renal cell carcinoma, cystic nephroma, mixed epithelial and stromal tumour of the kidney). These entities cannot be distinguished one from another on preoperative imaging studies. A preoperative biopsy and intra-operative frozen-section analysis do not lead to a correct diagnosis in many cases. Fortunately, the operative strategy is the same for all these tumours. In such cases, the nephron sparing surgery is indicated, whenever technically feasible, as almost all extensively cystic renal tumours have a good prognosis.
authors.affiliation: Department of Urology, Charles University Hospital, E. Benese 13, Plzen, 305 99, Czech Republic. horam@fnplzen.cz
authors.forename: Milan
authors.initials: M
authors.lastname: Hora
authors.forename: Ondrej
authors.initials: O
authors.lastname: Hes
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
authors.forename: Ludmila
authors.initials: L
authors.lastname: Boudová
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Chudácek
authors.forename: Boris
authors.initials: B
authors.lastname: Kreuzberg
authors.forename: Jirí
authors.initials: J
authors.lastname: Klecka
mesh_terms: D000328:Adult; D002292:Carcinoma, Renal Cell / Q000145:classification / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D012189:Retrospective Studies; D009396:Wilms Tumor / Q000473:pathology