title: Low incidence of benign lesions in resected suspicious renal masses greater than 2 cm: Single-center experience from Japan.
abstract: OBJECTIVE
  To assess the incidence of benign renal lesions in our Japanese clinical experience with surgical resection.
  
  
  METHODS
  A total of 411 renal masses harvested by radical or partial nephrectomy between January 1991 and April 2011 at our institution were retrospectively assessed. The incidence of benign lesions in 1-cm increments in diameter was determined, and a logistic regression model was used to assess relationships between the incidence of benign lesions and other factors.
  
  
  RESULTS
  Histological examination confirmed a total of 18 (4.4%) benign lesions. The incidence of benign lesions was 42.8% for nodules <1 cm and 10.0% for nodules 1 to <2 cm. In contrast, the incidence of benign lesions in each 1-cm increment between 2 and 6 cm was 4.1-4.9%. The incidence of benign lesions 2 to <4 cm was 4.8% and of benign nodules ≥6 cm was just 0-1.0%. The incidence of benign lesions ≥2 cm (3.5%) was significantly lower than that of masses <2 cm (16.2%; P < 0.001). Multivariate analysis showed that female gender (odds ratio 3.68) and smaller mass size (<2 cm; odds ratio 4.84) were significant predictors for benign lesions.
  
  
  CONCLUSIONS
  The incidence of benign lesions among renal masses ≥2 cm in diameter was found to be much lower than previously reported. This should be taken into account when designing strategies for the management of suspicious small renal masses.
authors.affiliation: Division of Nephro-Urologic Surgery and Andrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan. n-soga@aichi-cc.jp
authors.forename: Norihito
authors.initials: N
authors.lastname: Soga
authors.forename: Kouhei
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Takaki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yamada
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Arima
authors.forename: Norio
authors.initials: N
authors.lastname: Hayashi
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D007668:Kidney / Q000473:pathology*; D007680:Kidney Neoplasms / Q000453:epidemiology* / Q000473:pathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult