Over a 2-year period, 5 of 10 patients with revision of ventricular shunting were complicated by intraventricular and/or intracerebral hemorrhage due to avulsion of the choroid plexus. Retrospective analysis of computed tomography scans prior to the revision disclosed the presence of an intraventricular or periventricular mass adjoining the ventricular catheter in four of the five patients. Histologic findings of the soft tissue at the tip of the removed catheter were compatible with the choroid plexus accompanied by granulation tissue. The risk factors useful for detecting the possible occurrence of this complication are discussed. © 1990.