A rare cerebellar malformation: rhombencephalosynapsis.

Rhombencephalosynapsis is a rare cerebellar malformation characterized by absence of the vermis and midline fusion of hemispheres. It is easily recognized by MRI. No specific syndrome has been described in association with this cerebellar anomaly. Early diagnosis is possible especially when coexisting brain anomalies are present. We report a symptomatic case of rhombencephalosynapsis with moderate hydrocephalus.