The authors report an unusual case of superior vena cava thrombosis in an infant who subsequently developed communicating hydrocephalus; they also review previously reported cases of dural sinus hypertension, and separate them into two groups. Patients in the first group develop hydrocephalus and those in the second develop a pseudotumor-like syndrome. The former patients tend to have generalized increase in intracranial venous pressure while the latter have a normal pressure in some major intracranial venous structure(s). The absence of venous cushioning of the choroid plexus pulse wave is proposed as the cause of ventricular enlargement in the former group. In addition, patients in the large-ventricle group were younger than patients in the small-ventricle group.