title: Incidence of benign pathologic findings at partial nephrectomy for solitary renal mass presumed to be renal cell carcinoma on preoperative imaging.
abstract: OBJECTIVE
  To determine the incidence of benign pathologic findings at partial nephrectomy for a solitary renal lesion when preoperative imaging is reviewed by an experienced team of academic genitourinary radiologists.
  
  
  METHODS
  From 1996 to 2004, 143 patients underwent resection of a solitary renal lesion for presumed renal cell carcinoma amenable to partial nephrectomy. Our experienced team of genitourinary radiologists interpreted all preoperative imaging scans. Of the 143 patients, 44 underwent partial nephrectomy for a solitary lesion less than 2 cm, 85 for a lesion 2 to 4 cm, and 14 for a lesion greater than 4 cm.
  
  
  RESULTS
  Of the 143 solitary masses resected, 23 revealed benign pathologic findings (16.1%). Ten lesions (43.5%) were angiomyolipomas (AMLs), eight (34.8%) were oncocytomas, three (13.0%) were benign Bosniak-type cysts, and one each was a low-grade spindle cell lesion most consistent with mesoblastic nephroma, and a metanephric adenoma.
  
  
  CONCLUSIONS
  A significant fraction of small solitary renal masses presumed to be renal cell carcinoma had benign pathologic findings on resection, despite thorough expert radiologic review. Management should favor parenchyma-sparing approaches, because resection serves not only a therapeutic but also a diagnostic function. Patients should be counseled accordingly when faced with the diagnosis of renal mass.
authors.affiliation: Department of Surgery, Division of Urology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kutikov
authors.forename: Lindsay K
authors.initials: LK
authors.lastname: Fossett
authors.forename: Parvati
authors.initials: P
authors.lastname: Ramchandani
authors.forename: John E
authors.initials: JE
authors.lastname: Tomaszewski
authors.forename: Evan S
authors.initials: ES
authors.lastname: Siegelman
authors.forename: Marc P
authors.initials: MP
authors.lastname: Banner
authors.forename: Keith N
authors.initials: KN
authors.lastname: Van Arsdalen
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Wein
authors.forename: S Bruce
authors.initials: SB
authors.lastname: Malkowicz
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology; D018249:Adenoma, Oxyphilic / Q000453:epidemiology / Q000473:pathology; D000328:Adult; D018207:Angiomyolipoma / Q000453:epidemiology / Q000473:pathology; D002292:Carcinoma, Renal Cell / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D003560:Cysts / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D015994:Incidence; D007680:Kidney Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D009392:Nephrectomy; D018201:Nephroma, Mesoblastic / Q000453:epidemiology / Q000473:pathology