CLINICAL CASES 



465 



Fig. 316. — Mesial Section of the Brain, showing Large Pineal Cyst lying 

 between the splenium of the corpus callosum and the corpora 

 Quadrigemina. 



t» 





Ca. 



Gli. 



C.V. 



Fig. 317. — Case 9. 



A — Section through the wall of the pineal cyst shown in Fig. 316. The lumen 

 of the cyst lies below ; it is lined by a layer of condensed glial tissue, no 

 ependymal epithelium being visible. The middle zone is formed of a 

 degenerate tissue containing few parenchyma cells and showing numerous 

 spaces. In the upper part of the section is the fibrous capsule. 



Gli : glial tissue. Gl. st. : glial stratum. Lum. : lumen. 



B — Portion of the wall of the dorsal diverticulum or suprapineal recess which 

 lay above the pineal cyst. It shows sections of corpora arenacea and choroidal 

 villi. 



Ca. : corpus arenaceum. Cv. : choroidal villi. 



a wall lined with ependymal epithelium, and most probably containing tufts 

 of choroidal villi projecting into its lumen. 



Pineal cysts lined by ependyma also occur, and vary in size from small 

 microscopic cysts such as that shown in Fig. 304, in which the lining 

 30 



