Dandy walker syndrome can it occur in adults?

Not likely: Dandy walker malformation is a congenital problem, so if you have it, you have it from birth. Symptoms typically present early in life, some of which (like hydrocephalus) can be fatal, if left untreated. Milder variants of dandy walker, however, might not become apparent immediately or might be incidental findings on imaging later in life.

Dandy Walker: Dandy walker is almost always a congenital lesion, meaning present at birth. This disorder can remain asymptomatic in childhood and later become symptomatic as an adult but that is uncommon.