Exophytic mixed cystic/solid mass extending from sacrum

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  Variable size but often large, with potential for extremely rapid growth

  
  
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  Commonly extends into pelvis and abdomen

Solid tumors may have significant arteriovenous shunting

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  Color Doppler essential to evaluate vascularity

  
  
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  Scan every 1-3 weeks depending on size, vascularity, impending hydrops, and complications

Calculate tumor volume:fetal weight ratio (TFR)

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  Tumor volume: Tumor length x width x depth x 0.523

  
  
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  Divide by estimated fetal weight

  
  
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  TFR > 0.12 prior to 24 weeks has poor prognosis

Myelomeningocele in differential for cystic SCGT

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  Sac contains meninges + neural elements

  
  
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  Splayed posterior spinal ossification centers

  
  
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  Chiari 2 malformation of brain

Large, solid, vascular tumors have high mortality and morbidity; better outcome for cystic tumors

Prognosis significantly worse for fetus than neonate

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  Fetal diagnosis 30-50% mortality

Carefully assess for intrapelvic extension as it is part of surgical classification

Try to measure tumor in same plane each time

Evaluate for signs of impending cardiovascular compromise

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  Tumor growth, amniotic fluid index, placental thickness

  
  
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  Any signs of developing hydrops (skin edema, pleural or pericardial effusion, ascites)

Early vascular signs of high cardiac output state

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  Increased cardiothoracic ratio (> 50%)

  
  
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  Inferior cava diameter > 1 cm

  
  
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  Increase descending aortic velocity (> 120 cm/s)

Look for complications: Tumor rupture/hemorrhage