Development of syringohydromyelia associated with Dandy-Walker malformation: treatment with cystoperitoneal shunt placement. Case report.

Dandy-Walker malformation (DWM) is a well-described clinical entity, which includes vermian agenesis, posterior fossa cysts, and frequently, hydrocephalus. The authors report the clinical course and present the radiographic findings pertaining to a 1-month-old girl with DWM who was treated initially with a ventriculoperitoneal shunt and endoscopic fenestration of a posterior fossa cyst. After decompression for hydrocephalus, an increased mass effect at the foramen magnum from her posterior fossa cyst was demonstrated, as well as subsequent development of syringohydromyelia from C-4 to T-7. She was treated with a cystoperitoneal shunt. At the 6-month follow-up examination, the child (15 months of age) had achieved gains in developmental milestones, and complete resolution of the syrinx was established through MR imaging. This is the fourth nonautopsy pediatric case of DWM-associated syringohydromyelia reported in the literature and the third in a child to demonstrate impaction of the posterior fossa cyst at the foramen magnum leading to syrinx formation with subsequent treatment and resolution. Spinal imaging may be useful in the evaluation of patients with DWM who do not experience expected improvement after shunt procedures.