title: MRI features of renal oncocytoma and chromophobe renal cell carcinoma.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively describe the MRI features of the pathologically related entities renal oncocytoma and chromophobe renal cell carcinoma (RCC).
  
  
  METHODS
  Twenty-eight cases of histologically proven renal oncocytoma and 15 of chromophobe RCC evaluated with preoperative MRI from January 2003 through June 2009 at our institution were independently reviewed for an array of MRI features by two radiologists blinded to the final histopathologic diagnosis. These features were tabulated and compared between chromophobe RCC and renal oncocytoma by use of the Mann-Whitney test and binary logistic regression.
  
  
  RESULTS
  Renal oncocytoma and chromophobe RCC showed no significant difference in size or any of 16 qualitative imaging features (p = 0.0842-1.0, reader 1; p = 0.0611-1.0, reader 2). Microscopic fat, hemorrhage, cysts, infiltrative margins, perinephric fat invasion, renal vein invasion, enhancement homogeneity, and hypervascularity were each observed in less than 20% of cases by both readers. A central scar and segmental enhancement inversion (a recently described finding in which early contrast-enhanced images show relatively more enhanced and less enhanced intralesional components with inversion of their relative enhancement on later images) were observed by both readers in at least 10% of cases of both renal oncocytoma and of chromophobe RCC with no significant difference between the two entities (p = 0.2092-0.2960).
  
  
  CONCLUSIONS
  We have presented the largest series to date of the MRI features of both renal oncocytoma and chromophobe RCC. These related entities exhibited similar findings, and no MRI features were reliable in distinguishing between them.
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 560 First Ave., TCH-HW202, New York, NY 10016, USA. Andrew.Rosenkrantz@nyumc.org
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.forename: Nicole
authors.initials: N
authors.lastname: Hindman
authors.forename: Erin F
authors.initials: EF
authors.lastname: Fitzgerald
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Niver
authors.forename: Jonathan
authors.initials: J
authors.lastname: Melamed
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
mesh_terms: D018249:Adenoma, Oxyphilic / Q000473:pathology*; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media