Symptomatic choroidal epithelial cyst in the fourth ventricle.

A case of choroidal epithelial cyst in the fourth ventricle is described. The cyst occupied the fourth ventricle almost completely, and produced an intermittent hemiparesis and hemisensory disturbance. After removal of the cyst wall, the patient recovered completely. On light microscopy, a single epithelial layer with a basement membrane lining the cyst wall was observed. An electron microscopic study was also made.