HISTORY:
                    
                 Patient is a female in her 20s who presented with abdominal and back pain found to have a right renal mass. MRI showed a 4.1cm multi-cystic mass arising from the lower pole of the kidney. The patient then proceeded with robotic right partial nephrectomy (lower pole heminephrectomy). 
                    
                   
                  
                    
GROSS:
                    
                     
                  
                
                
                 
                 
                 
                
                
                     
                     
 
                  
                
                    
                 
                            What is the most likely diagnosis?
                            
                               - Cystic nephroma
 
                                - Mixed epithelial and stromal tumor
 
                                - Synovial sarcoma
 
                                - Angiomyolipoma with epithelial cysts
        
                            
                          
                       
                         
                        
                         
                            
                            
                           Mixed epithelial and stromal tumor