Splenic Cyst

Spectrum of appearances on CT

• Solitary, well-defined, water density, unilocular cystic lesion

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    Thin wall with sharp interface to normal splenic tissue

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    No peripheral/intracystic enhancement or solid component

• Some cysts can have septations, trabeculations, thick wall, internal necrotic debris, or calcification

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    May have attenuation greater than simple fluid (due to hemorrhage or protein)

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    Thin eggshell calcification or thick, irregular peripheral calcification

• Congenital and acquired cysts may be indistinguishable

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    Congenital cysts more likely simple in appearance

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    Acquired cysts often complex with calcification

Splenic infection and abscess

• Pyogenic/fungal abscess or parasitic echinococcal cyst

Splenic metastases and lymphoma

Benign primary splenic tumors

Intrasplenic pseudocyst

Congenital epidermoid ("true" cyst)

• May be due to intrasplenic sequestration of peritoneal mesothelial cells during embryologic development

Acquired cysts (secondary/"false" cysts or pseudocysts)

• Due to prior trauma, hematoma, infarction, or infection

• Majority of splenic cysts in North America due to prior trauma

• Arise due to liquefactive necrosis and cystic change

Most cysts are discovered incidentally on imaging

Small and asymptomatic: No treatment

Symptomatic cysts usually treated, with options including percutaneous aspiration/drainage, cyst decapsulation or unroofing, and partial/complete splenectomy

• Splenectomy for symptomatic large cysts (> 5 cm)

Best diagnostic clue

• Sharply defined, spherical cystic lesion of water density

Key concepts

• Classification

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    Congenital epidermoid cysts (primary or "true" cyst)

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      Demonstrate inner cellular endothelial lining

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      Account for 10-25% of all splenic cysts

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    Acquired cysts (secondary or "false" cysts)

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      No inner cellular lining but have fibrous wall

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      Account for 80% of splenic cysts

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      Due to prior trauma, hematoma, or infarction

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      Development of cyst due to liquefactive necrosis

Curvilinear wall calcification in left upper quadrant

Spectrum of appearances

• Solitary, well-defined, water density unilocular cyst

  • –

    Thin wall with sharp interface to normal splenic tissue

  • –

    No peripheral or intracystic enhancement; no solid, nodular soft tissue component

  • –

    Always intraparenchymal (no exophytic component)

• Some cysts can have septations, trabeculations, thick wall, and internal necrotic debris

  • –

    May have attenuation greater than simple fluid (due to hemorrhage or protein)

• Cysts may have thin eggshell calcification or thick, irregular peripheral calcification

Congenital and acquired cysts may be indistinguishable

• Congenital cysts more likely to be simple in appearance

• Acquired cysts more likely complex with calcification