What is the typical ultrasound appearance of a complete hydatidiform mole?

A complete hydatidiform mole classically shows a 'snowstorm' or 'cluster of grapes' appearance on ultrasound - a uterus filled with multiple small cystic (vesicular) spaces (the swollen chorionic villi), with no fetus or fetal parts.

Theca lutein cysts (bilateral enlarged ovaries) may also be seen. The hCG is usually very high.

Clinical relevance. Recognising the 'snowstorm'/'cluster of grapes' ultrasound appearance (with no fetus) helps diagnose a complete hydatidiform mole.

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Ultrasound appearance of a complete mole

Ultrasound is key to diagnosing a complete hydatidiform mole.

Classic appearance

• A 'snowstorm' or 'cluster of grapes' / 'bunch of grapes' appearance - the uterus is filled with multiple small cystic (vesicular) spaces, representing the hydropic (swollen) chorionic villi.
• No fetus or fetal parts (and no amniotic fluid/gestational sac with a fetus) - a complete mole has no fetal tissue.

Associated findings

• Theca lutein cysts - bilaterally enlarged, multicystic ovaries (from high hCG) may be seen.
• The uterus may be large for dates.

Supporting features

• Markedly elevated hCG.

Note

• A partial mole may show a fetus (often abnormal/non-viable) with focal cystic placental changes - a less classic appearance.
• Early moles may look like a missed miscarriage, with diagnosis confirmed on histology.