title: Bosniak category IIF and III cystic renal lesions: outcomes and associations.
abstract: OBJECTIVE
  To evaluate clinical outcomes, pathologic subtypes, metastatic disease rate, and clinical features associated with malignancy in Bosniak category IIF and III cystic renal lesions.
  
  
  METHODS
  This retrospective study was institutional review board approved and HIPAA compliant. Informed consent was waived. Radiology and hospital information systems were searched for Bosniak IIF and Bosniak III lesions in computed tomographic (CT) reports from January 1, 1994 to August 31, 2009. Patients 18 years and older with unenhanced and contrast material-enhanced CT results and with lesions either surgically resected or with 1 year or more of surveillance were included. Data recorded were history of renal cell carcinoma, number of renal lesions, presence of a coexistent solid renal mass, surgical pathologic findings, and presence of metastatic disease from a renal malignancy. Sixty-two patients with 69 Bosniak IIF lesions and 131 patients with 144 Bosniak III lesions were identified. Proportions from independent groups were compared by using the Fisher exact test; continuous variables were compared by using a two-tailed two-sample t test or a Wilcoxon two-sample test.
  
  
  RESULTS
  The malignancy rate of resected Bosniak IIF lesions was 25% (four of 16) and that for Bosniak III lesions was 54% (58 of 107) (P = .03). Thirteen percent (nine of 69) of Bosniak IIF lesions progressed at follow-up, and 50% (four of eight) of these resected cysts were malignant. History of primary renal malignancy, coexisting Bosniak category IV lesion and/or solid renal mass, and multiplicity of Bosniak III lesions were each associated with an increased malignancy rate in Bosniak III lesions. No patients developed locally advanced or metastatic disease from a Bosniak IIF or III lesion.
  
  
  CONCLUSIONS
  Although the malignancy rate in surgically excised Bosniak IIF and Bosniak III cystic renal lesions was 25% and 54%, respectively, in our study, the malignancy rate was higher in patients with a history of primary renal malignancy or coexisting Bosniak IV lesion and/or solid renal neoplasm.
authors: Section of Abdominal Imaging, Imaging Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, A21, Cleveland, OH, 44195, USA.
authors: Andrew D
authors: AD
authors: Smith
authors: Erick M
authors: EM
authors: Remer
authors: Kelly L
authors: KL
authors: Cox
authors: Michael L
authors: ML
authors: Lieber
authors: Brian C
authors: BC
authors: Allen
authors: Shetal N
authors: SN
authors: Shah
authors: Brian R
authors: BR
authors: Herts
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media