title: CT of the kidneys: what size are renal cell carcinomas when they cause symptoms or signs?
abstract: OBJECTIVE
  To investigate the size of renal cell carcinomas (RCCs) when they cause macroscopic hematuria or other symptoms and/or signs.
  
  
  METHODS
  A retrospective review of 232 patients (136 males, 96 females; mean age 68 +/- 11 years; age range 40-90 years) with a diagnosis of RCC was undertaken. Patients were grouped according to the presenting symptoms and/or signs caused by the RCCs. Tumor size was measured on CT images.
  
  
  RESULTS
  Of the RCCs, 29% were found incidentally and 71% caused symptoms and/or signs. The incidentally found RCCs measured 4.9 +/- 2.6 cm (range 2-12 cm) and RCCs causing symptoms and signs measured 8.9 +/- 3.2 cm (range 3-18 cm); this size difference was significant (p < 0.001). None of the RCCs causing macroscopic hematuria were <4 cm in size and only 3/165 (2%) of the symptomatic RCCs were <4 cm in size.
  
  
  CONCLUSIONS
  If small (<4 cm) RCCs do not cause symptoms, patients with them will not be referred for CT or any other imaging modality. Therefore, if a 2-cm RCC is found in a patient presenting with macroscopic hematuria, it is unlikely that this small RCC caused the hematuria and another cause of the hematuria must be ruled out.
authors.affiliation: Department of Radiology, Uppsala University Hospital, Uppsala, Sweden. par.dahlman@radiol.uu.se
authors.forename: Pär
authors.initials: P
authors.lastname: Dahlman
authors.forename: Einar
authors.initials: E
authors.lastname: Brekkan
authors.forename: Anders
authors.initials: A
authors.lastname: Magnusson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000209:etiology; D002292:Carcinoma, Renal Cell / Q000150:complications* / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006417:Hematuria / Q000209:etiology; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology; D007680:Kidney Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed