We report on a 32-year-old woman who presented with headache of a 10-day duration, due to acute hydrocephalus. This was a result of a tumefactive lesion of the posterior fossa, which was later proven to be a cerebellar venous infarct caused by unilateral transverse sinus thrombosis. Cerebral dural sinus thrombosis should be considered in the differential diagnosis of new onset of headache.