Benign intraparenchymal brain cysts without an epithelial lining.

Three patients are presented who had benign intraparenchymal cysts of the brain. The wall of each cyst was biopsied and had no epithelial lining or other microscopic feature to indicate the etiology of the cyst. The authors review published information about benign brain cysts and speculate about the origin of those having a wall composed solely of neuroglial tissue.