title: Pathological characteristics and radiographic correlates of complex renal cysts.
abstract: OBJECTIVE
  To characterize pathological and cancer-specific outcomes of surgically resected cystic renal tumors and to identify clinical or radiographic features associated with these outcomes.
  
  
  METHODS
  All patients at our institution who underwent radical or partial nephrectomy for complex renal cystic masses between 2004 and 2011 with available computed tomographic imaging were included. The Bosniak score was determined, as were 10 specific radiographic characteristics of renal cysts in patients with preoperative imaging available for review. These characteristics were correlated with cystic mass histopathology. Recurrence-free survival after surgery was determined.
  
  
  RESULTS
  Overall, 133 patients underwent renal surgery for complex cystic lesions, 89 (67%) of whom had malignant lesions. Malignancy risk increased with Bosniak score (P≤0.01) and presence of mural nodules (P = 0.01). Most (63%) malignancies demonstrated clear cell histology. The papillary renal cell carcinomas (25%) exhibited lower enhancement levels (P = 0.04) and were less often septated (P<0.01). Of the malignancies, 79% were low stage (pT1), and 73% were Fuhrman grade 1 or 2. Large cyst size was associated with advanced tumor stage (P = 0.05). Neither Bosniak score nor any other radiographic parameter was associated with Fuhrman grade. In 70 patients with a median follow-up of 43 months, only 1 (1.4%) developed disease recurrence.
  
  
  CONCLUSIONS
  Most cystic renal malignancies are low-stage, low-grade lesions. Papillary renal cell carcinomas account for nearly a quarter of cystic renal malignancies and have unique radiographic characteristics. Disease recurrence after surgical resection is rare. These findings suggest an indolent behavior for cystic renal tumors, and these lesions may be amenable to active surveillance.
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD. Electronic address: adam.reese@tuhs.temple.edu.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Reese
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Pamela T
authors.initials: PT
authors.lastname: Johnson
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gorin
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Pierorazio
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Mohamad E
authors.initials: ME
authors.lastname: Allaf
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Elliot K
authors.initials: EK
authors.lastname: Fishman
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: George J
authors.initials: GJ
authors.lastname: Netto
authors.affiliation: Department of Urology, Temple University School of Medicine, Philadelphia, PA; The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Pavlovich
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology*; D003560:Cysts / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed
keywords: Cysts; Kidney; Renal cell carcinoma; X-ray computed tomography