Background: Cerebellar swelling with obstructive hydrocephalus is a rare but life threatening condition, associated with different etiologies, familial hemophagocytic lymphohistiocytosis (HLH) being rarely one of them.
Patient: 2-year-7-month old boy presented with irritability, cerebellar dysfunction, and somnolence. Brain MRI showed marked diffuse cerebellar swelling and obstructive hydrocephalus with mild tonsillar herniation.