Right parietal V-P shunt in situ. No hydrocephalus. Extra-axial spaces are mildly prominent but there is no overt subdural collection to suggest over shunting.
Typical features of Chiari 2 malformation with more than 25 mm of cerebellar tonsillar ectopia, small posterior fossa, towering cerebellum, peaked tectal plate, callosal dysgenesis with hypoplastic body and splenium and associated colpocephaly, fenestrated falx with gyral interdigitation, diffuse posterior predominant stenogyria and large massa intermedia. The clivus is vertically oriented and the sella is shallow with superior convexity of the pituitary, projecting into the suprasellar cistern, and relative inferior displacement of the posterior pituitary bright spot.
No other gross midline abnormality. In particular, the optic chiasm is unremarkable. No evidence of a syrinx in the imaged upper cervical cord.