Rhombencephalosynapsis
Findings:
The cerebellar hemispheres are fused, without a normal
vermis identified.
Discussion:
Rhombencephalosynapsis is a rare posterior fossa malfomation
in which there is absent or hypoplastic vermis and midline fusion of the
cerebellar hemispheres. Associated midline anomalies include fusion of
the tectum, fused thalami, callosal dysgenesis, and absent septum pellucidum.