title: Renal Collision and Composite Tumors: Imaging and Pathophysiology.
abstract: OBJECTIVE
  To illustrate the imaging appearances of a spectrum of renal collision and composite tumors. Occurrence of collision and composite tumors in the genitourinary tract is rare compared to the usual occurrence of synchronous tumors.
  
  
  METHODS
  Case studies were chosen that represent the different tumors. Analysis was made on both the imaging and the pathology if excision was performed.
  
  
  RESULTS
  Presence of 2 different cell types can lead to confusing imaging findings, and biopsy or excision is typically needed for final diagnosis. Some composite tumors have a characteristic appearance on imaging based on their pathologic features.
  
  
  CONCLUSIONS
  Familiarity with imaging findings may help radiologists include these tumors in their differential diagnosis.
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Chandana
authors.initials: C
authors.lastname: Lall
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Roozbeh
authors.initials: R
authors.lastname: Houshyar
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Jaime
authors.initials: J
authors.lastname: Landman
authors.affiliation: Department of Radiology, University of Cincinnati Medical Center, Cincinnati, OH.
authors.forename: Sadhna
authors.initials: S
authors.lastname: Verma
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Martin
authors.initials: M
authors.lastname: Goyenechea
authors.affiliation: Department of Radiology, University of Washington, VA Puget Sound Health Care System, Seattle, WA.
authors.forename: Puneet
authors.initials: P
authors.lastname: Bhargava
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Pulford
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA. Electronic address: Zokhunov@uci.edu.
authors.forename: Zhamshid
authors.initials: Z
authors.lastname: Okhunov
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Parwiz J
authors.initials: PJ
authors.lastname: Siaghani
authors.affiliation: Department of Radiology, Mayo Clinic, Scottsdale, AZ.
authors.forename: Christine
authors.initials: C
authors.lastname: Menias
mesh_terms: D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000473:pathology*; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed