title: Pathologic concordance of sporadic synchronous bilateral renal masses.
abstract: OBJECTIVE
  To review the collective experience evaluating pathologic concordance rates of sporadic bilateral synchronous renal tumors reported in the Surveillance, Epidemiology, and End Results (SEER) database and the published English literature and treated at Fox Chase Cancer Center; specifically, to analyze concordance rates of malignant versus benign disease, histologic type, tumor stage, and nuclear grade.
  
  
  METHODS
  We reviewed the SEER database, the published English language literature, and our own institutional tumor registry to identify all cases of sporadic, synchronous localized (cT1-3N0M0) bilateral renal masses. Malignant and benign concordance rates were defined as agreement of any benign or malignant tumor type bilaterally. Histologic concordance was defined as bilateral histologic agreement. Tumors with mixed histologies were discordant unless all patterns were identical bilaterally. Nuclear grades were concordant if bilateral tumors were either "high" grade or "low" grade.
  
  
  RESULTS
  The malignant concordance rate in the SEER data was 99% (273 of 274), and benign concordance was 0 (0 of 1). In the published literature and Fox Chase Cancer Center series, malignant concordance rates ranged from 84% to 95%, whereas benign concordance ranged from 39% to 67%. The SEER data revealed a histologic concordance rate of 93% (256 of 274), and nuclear grade concordance was 85% (88 of 103).
  
  
  CONCLUSIONS
  These data demonstrate that in cases of bilateral sporadic localized synchronous renal masses, a diagnosis of ipsilateral renal cell carcinoma is associated with contralateral renal cell carcinoma in the vast majority of patients, whereas ipsilateral benign pathology is associated with contralateral benign disease at a substantially lower rate. Histologic concordance is similarly high, meaning most cases of clear cell or papillary tumors ipsilaterally are concordant in the contralateral kidney. Concordance rates of nuclear grade were slightly lower. These data are important when counseling and managing patients with bilateral synchronous sporadic renal tumors.
authors.affiliation: Department of Urologic Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Rothman
authors.forename: Paul L
authors.initials: PL
authors.lastname: Crispen
authors.forename: Yu-Ning
authors.initials: YN
authors.lastname: Wong
authors.forename: Tahseen
authors.initials: T
authors.lastname: Al-Saleem
authors.forename: Eric
authors.initials: E
authors.lastname: Fox
authors.forename: Robert G
authors.initials: RG
authors.lastname: Uzzo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000473:pathology*