CHOROIDAL papillomas are of general interest because of their combined pathologic and physiologic implications. As in the case included in this report, through such papillomas evidence may be afforded as to the pathogenesis of the associated hydrocephalus. Since the survey of 86 cases by Posey122 additional cases of choroidal papilloma have been reported.2The earliest report, by Van Wagenen,3of 33 cases, indicated a high incidence in the younger age groups. The fourth ventricle was predominantly the location both in the older patients and in the over-all series, but the lateral ventricles were the usual site in the very young. Posey's survey and subsequent reports have made little alteration in these statistical results. In the most recently reported series2d, fthe average age has been somewhat higher. In one series2fthe predominant location was the fourth ventricle. In the other2dthe commonest location