Etiology of ventriculomegaly in choroid plexus papilloma.

In order to test the hypothesis that overproduction of cerebrospinal fluid can cause the hydrocephalus seen in choroid plexus papillomas, adult mongrel dogs with and without hydrocephalus were subjected to high pressure intraventricular infusions of artificial cerebrospinal fluid (CSF). Pre- and postinfusion volumes were calculated, using a new method for on-line measurement of ventricular volume involving linear measurements from Conray ventriculograms. Ventricular volumes increased an average of 8% in 36 h. The dogs previously made hydrocephalic by the intracisternal injection of kaolin had a significant volume increase (34% in 36 h). Overproduction of CSF alone can produce hydrocephalus, but the presence of hydrocephalus in choroid plexus papillomas is more likely to be a result of the complex interaction of CSF overproduction and partial restriction of CSF flow.