title: Renal oncocytoma: contrast-enhanced sonographic features.
abstract: OBJECTIVE
  The purpose of this study was to illustrate the features of renal oncocytoma on contrast-enhanced sonography.
  
  
  METHODS
  Five cases of surgical pathologically proven renal oncocytoma were retrospectively reviewed and analyzed in this study. The 5 patients studied included 3 men and 2 women with a mean age of 52.3 years (range, 32-66 years). All patients underwent conventional and contrast-enhanced sonographic examinations before surgery. The sonographic features, enhancement pattern, and dynamic perfusion change of the tumors and renal parenchyma in vascular phases were evaluated and compared to computed tomography.
  
  
  RESULTS
  On grayscale sonography, renal oncocytomas appeared as solitary hypoechoic or isoechoic masses originating from the renal cortex measuring 2 to 6 cm with a well-defined margin. Color Doppler flow imaging showed rich blood flow signals in the periphery and striplike blood flow signals within the masses. On contrast-enhanced sonography, the features of these tumors included early enhancement, hyperenhancement, and fast wash-out compared to the adjacent renal cortex. There were irregular nonenhanced areas seen in the center of the masses (n = 3) and nonenhanced thin rims seen in the periphery (n = 5). Macroscopically, the well-marginated tumors were yellowish brown with a tender texture and were located in the renal cortex. Central irregularly shaped fibrous scars were seen in 3 tumors, consistent with nonenhanced areas on contrast-enhanced imaging.
  
  
  CONCLUSIONS
  Contrast-enhanced sonography can provide valuable hemodynamic information on renal oncocytoma, which may help in making a differential diagnosis of this benign renal tumor in clinical practice.
authors: Department of Ultrasound, Shanghai First People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors: Ying
authors: Y
authors: Wu
authors: Lianfang
authors: L
authors: Du
authors: Fan
authors: F
authors: Li
authors: Huiping
authors: H
authors: Zhang
authors: Yingyu
authors: Y
authors: Cai
authors: Xiao
authors: X
authors: Jia
mesh_terms: D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride