Communicating hydrocephalus secondary to a cardiac tumour compressing the superior vena cava.

An infant developing communicating hydrocephalus as a result of a rare cardiac tumour compressing the superior vena cava is reported. The development and regression of the hydrocephalus parallels the degree of obstruction to venous outflow. This finding is reviewed in the light of previous studies and case reports, and it is argued that the hydrocephalus is secondary to a reversible defect in cerebrospinal fluid absorption caused by the reversal of the normal cerebrospinal fluid to sagittal sinus pressure gradient.