KEY FACTS
Imaging
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Abdominal cyst in female fetus typically located in lower lateral abdomen or pelvis
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Large cysts may extend into upper abdomen
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Well circumscribed, generally anechoic, unilocular, avascular with imperceptible walls
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May have occasional septations
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Daughter cyst sign: Small follicle along wall of cystic mass
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Highly specific for ovarian origin
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82% sensitive
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May be bilateral
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If cyst is seen before 3rd trimester, it is very unlikely that it is ovarian in origin
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Fetal ovaries are too immature to respond to maternal/placental hormones before 3rd trimester
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Scanning Tips
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Check fetal sex
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Ovarian cyst is most common cause of intraabdominal cyst in female fetus
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Male sex excludes diagnosis
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Confirm normal appearance of gastrointestinal and hepatobiliary systems
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Use high-resolution transducer to characterize cyst wall
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Layered gut signature in cyst wall is diagnostic of enteric duplication cyst
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Confirm normal urinary tract
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High number of cystic abdominal masses are related to urinary tract
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Comment on size
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Large cyst (> 6 cm) associated with increased risk of hemorrhage and torsion
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Consider torsion if
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New fluid-fluid level
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Previously anechoic or hypoechoic cyst becomes hyperechoic
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