HISTORY:
                   45 year old female with a history of a left lateral thigh mass. Ultrasound reveal a large heterogeneous mixed echogenic solid cystic hypoechoic lesion anterior to the left hip joint likely represents a large complex collection/hematoma. Possibility of a neoplastic lesion cannot be entirely excluded.
                        
                    Magnetic resonance imaging (MRI) demonstrated a large 9.8 x 12.1 x 14.3 cm complex collection in the left lateral thigh. Imaging characteristics were be consistent with a hematoma although underlying neoplastic process is difficult to completely exclude.
                        
                    
                    
                 
                 
                    GROSS:
                   Gross: The specimen is designated as “left thigh mass” and consists of a 1,111 gram, 15.5 x 13.2 x 13.1 cm cystic mass with attached yellow-pink soft tissue. Cut section through the mass reveals extensively necrotic tissue, approximately 75% cystic and 25% solid.  Areas of necrosis appear to occupy approximately 90% of the mass.  The cystic component is filled with blood-tinged mucinous material.  The solid component of the mass is pink-white and gelatinous.  
                      
                    
                 
						
                
                         
			             
                       
			             
			             
                       
                         
                       
                       
                       
			            
              
                       
                
                    
                 
                            What is the most likely diagnosis?
                            
                               - Leiomyosarcoma
 
                               - Malignant peripheral nerve sheath tumor
 
                               - Spindle cell rhabdomyosarcoma
 
                               - Dedifferentiated liposarcoma
 
                            
                            
                          
                       
                         
                        
                         
                            
                         
                          Malignant peripheral nerve sheath tumor