Hematoma: Localized collection of blood outside of blood vessel

Seroma: Serous fluid collection within soft tissues (plasma exudate from small blood vessels)

Lymphocele: Collection of lymphatic fluid due to leakage/damage to lymphatics

Hematoma

• ○
  

  Acute

  
  
  
  
  • –
    

    Heterogeneous pseudosolid appearance and can be echogenic or isoechoic

    
    
  • –
    

    Underlying cause of hematoma such as muscle tear or vascular malformation may be apparent

    
    
  • –
    

    No internal blood flow unless active bleeding

    
    
  • –
    

    Surrounding edema

  
  
  
  
• ○
  

  Subacute/chronic

  
  
  
  
  • –
    

    Mild peripheral hyperemia

    
    
  • –
    

    Decrease in size and become more echogenic around periphery over time

    
    
  • –
    

    Layered appearance of fluid and solid debris from separation of cellular elements and serum

    
    
  • –
    

    Solid matter retracts and remaining portion “liquefies” seen as cystic spaces or hypoechoic fluid

  
  
  
  
• ○
  

  Organizing hematoma

  
  
  
  
  • –
    

    Encapsulated with fibrous wall preventing reabsorption and allows for rebleeding

    
    
  • –
    

    Mimics soft tissue mass

  
  

Seroma

• ○
  

  Echo-poor or anechoic with strong posterior acoustic enhancement

  
  
• ○
  

  Absent or barely discernible wall depending on chronicity

  
  
• ○
  

  Often near site of surgery (chest wall, abdomen, groin)

Lymphocele

• ○
  

  Unilocular and thin walled; indistinguishable sonographically from seroma

  
  
• ○
  

  Occurs post surgery and is common after lymphadenectomy

Hematoma can occur from minor trauma or spontaneously in patients on anticoagulation or with coagulopathy

Unexplained, unusual, or nonresolving hematoma should raise concern for soft tissue mass

Serial follow-up is helpful to confirm hematoma and to check for underlying cause

Hematoma can be distinguished from seroma/lymphocele with ultrasound; seroma and lymphocele are differentiated by fluid analysis

Seroma/lymphocele may need treatment with aspiration &/or pressure bandaging

Always assess suspected fluid collection with color Doppler to avoid missing mass or vessel

Use color and spectral Doppler around periphery of hyperacute hematoma to assess for active bleeding

Seroma can have thin septa and jiggles like bowl of Jell-O with agitation

Assess for mass effect on adjacent structures (i.e., hydronephrosis in transplant kidney)