Rhombencephalosynapsis in a 19-month-old boy

Rhombencephalosynapsis in a 19-month-old boy with congenital hydrocephalus secondary to aqueductal stenosis, severe psychomotor retardation, and who died of shunt complications. (A) Coronal view of pons and cerebellum showing absence of vermis and fusion of medial sides of cerebellar hemispheres, with preservation of fourth ventricle. MRI-T1. (B) Histopathological transverse section of pons and cerebellum corresponding to MRI view in (A). The absence of the vermis with hemispheric fusion is confirmed. There also is fusion of the dentate nuclei in the deep cerebellar white matter. Luxol fast blue and Nissl stain. (Courtesy of Professor Peter Barth, University of Amsterdam.)