CLINICAL CASES 457 



by the tumour forwards and outwards. This tumour had evidently arisen from 

 the pineal region, the tumour lying mostly to the left side of this, pushing 

 downwards the corpora quadrigemina and lamina quadrigemina and com- 

 pressing the subjacent aqueduct of Sylvius, thus producing the hydro- 

 cephalus. The body of the pineal gland was still present, about the size of a 

 small cherry-stone, and apparently more or less independent of the tumour, 

 which, however, was in contact with its upper and left surface. The central 

 portion of the pineal was removed for section, and the remaining sides of the 

 gland sewn together to preserve the continuity of the specimen. The tumour 

 was about the size of a large walnut or small plum, and it reached and pushed 

 downwards and backwards the upper and anterior part of the cerebellum. 



On the right side of the brain, just external to the dilated posterior ventri- 

 cular horn, there was considerable softening and haemorrhage due to the com- 

 pression, and the cerebrospinal fluid had evidently ruptured outwards at this 

 point during the removal of the specimen. The right optic thalamus showed 

 considerable bulging into the dilated right lateral ventricle, suggesting the 

 possibility that this also contained tumour, but on cutting into it, this was dis- 

 proved and it was found to be due merely to pressure displacement by the 

 tumour to the left side, pushing it towards the right and upwards. Sections of 

 the tumour itself had a glistening, pearly white iridescence, suggestive of the 

 presence of cholesterol. Horizontal sections at a lower level showed much the 

 same appearance, with dilatation of the ventricles, including the third ventricle, 

 thus producing the prominent infundibulum as seen from below. 



Histological Examination — Sections from various parts of the pearly tumour 

 showed it to be a typical epidermoid consisting of a series of cysts or tumours, 

 showing a concentric laminated appearance due to the production from the 

 periphery inwards of squamous epithelium The outer or formative layer in 

 most of these cysts is much degenerated or has largely disappeared, i.e. is now 

 more or less inactive. Where it persists it shows a tendency to the production 

 of multinucleated plasmoidal squamous cells. Here and there, however, the 

 formation of outward budding and the production of further small cysts at the 

 periphery of the main mass persist. The central portions of the cysts consist 

 of desquamated epithelial cells and debris, including cholesterol crystals. 



Sections of the pineal itself show at some parts more or less normal pineal 

 structure, but at others there is distinct proliferation, with the production of 

 what may be considered a simple pinealoma, involving more especially the larger 

 pineal cells, and with little or no proliferation of the so-called " small lymphocyte- 

 like " cells. 



The adenomatous cells are somewhat loosely arranged, the stroma varying 

 in amount and in some parts being scanty and containing numerous thin- 

 walled blood-vessels. 



Case 5. — George W., aged 32, came under observation in March, 1932, 

 complaining of giddiness and some difficulty in walking. The patient was a 

 bank clerk, and was able to do his work until February, 1932, when he had an 

 attack of influenza which kept him in bed for three weeks. On getting out of 

 bed he found he was very unsteady on his feet and could not stand alone. He 

 was treated with tonics and massage, but did not improve. 



