11.5243
 

 
Boy,   2 years   3 months
 
Clinic: Progressive    abdominal  swelling.
 
Intraoperative:  20 x 20 x 15 cm     firm,  well-capsulated  mass  in the left half of   retroperitoneum. No  evidence of    gross  infiltration.
 
Problem: Is  this  a  malignant tumor ?-   and  origin ?
 
There  is  capular invasion  (Images  "border"),  there is  necrosis,   but  there  are    few  mitotic  figures (<1/10HPF), and  overall  the  cells  are not  highly  atypical (no  nucleoli).  Thanks !