Fetal rhombencephalosynapsis

Case contributed by Dr Alexandra Stanislavsky


Suspected cerebellar dysgenesis/hypoplasia on second trimester ultrasound.

Patient Data

Age: 25W 2D GA
Gender: Female

There is no evidence of a normal vermis.  Instead, the cerebellar hemispheres are closely opposed to one another. The cerebellum has a ball shape, typical for rhombencephalosynapsis. In addition, the morphology of fourth ventricle is abnormal. Instead of being an equilateral triangle, it has a rounded appearance and is much larger than normal. 

Case Discussion

Typical features of rhombencephalosynapsis on fetal MRI.

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