All tumors (benign and malignant) can have variable appearances, a lot of overlap by US

Benign tumors

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  Hemangioma: #1 benign splenic tumor; typically small, echogenic, incidental, asymptomatic

  
  
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  Hamartoma: Typically echogenic, homogeneous

  
  
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  Lymphangioma: Typically hypoechoic, loculated, avascular; younger age

  
  
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  Littoral cell angioma: Rare; variable appearance, splenomegaly

Malignant tumors

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  Lymphoma (Hodgkin disease, non-Hodgkin lymphoma, primary splenic, AIDS-related), leukemia, myeloproliferative disorders

  
  
  
  
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    Classic: Diffuse SMG; if focal: Hypoechoic, indistinct margins

    
    
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    3 macroscopic patterns: Diffuse/infiltrative, miliary/nodular, focal hypoechoic

  
  
  
  
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  Metastasis (breast, lung, ovary, stomach, melanoma)

  
  
  
  
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    Cystic, solid, or mixed; can be targetoid lesions

  
  
  
  
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  Primary splenic malignancies very rare (angiosarcoma most common of these)

Splenic infarct

Splenic infection/abscess

Splenic cyst

Splenic hematoma

Hepatosplenic sarcoidosis

Primary splenic malignancies are rare; biggest diagnostic dilemma is usually indeterminate splenic lesion in patients with extrasplenic malignancy (i.e., is it metastasis or not)

Considerable overlap in US findings; reliable differentiation on imaging is not always possible, requires histology

Color Doppler vascularity may be helpful if present (to conclude not cyst), but absent color flow does not entirely exclude benign or malignant tumor

Isolated splenic metastases and primary splenic malignancies are rare; most splenic metastases are seen in setting of widespread metastatic disease, including liver