CHAPTER 29 



PATHOLOGY OF PINEAL TUMOURS 



The various pathological conditions which arise in and around the pineal 

 gland can be discussed in relation to the actual lesion itself, in relation to 

 the local changes produced inside the cranium, and in relation to the 

 somewhat variable general skeletal and endocrine changes which are 

 sometimes associated with such pathological conditions. 



General Pathology. — The pineal gland may undergo simple hyper- 

 trophy. This was described by Virchow as occurring in an infant. It 

 has also been observed in association with other pathological conditions, 

 such as myxoedema and polyglandular dysfunctions, and has also been 

 described in a case of general cerebral hypertrophy. 



Laignel has observed and described a case in which atrophy of the 

 gland was found. 



The other pathological conditions arising in and in the region of the 

 pineal may be classified as follows : (1) cysts ; (2) cholesteatomata ; 

 (3) teratomata ; (4) pinealomata ; (5) pineoblastomata. 



1. Cysts. — Cysts of various types have been described in relation to 

 the pineal. They are usually simple cysts without any associated tumour 

 growth. Often they may be found to project into and obliterate the 

 third ventricle and to compress the corpora quadrigemina. They almost 

 invariably give rise to hydrocephalus by blockage of the aqueduct. 



No rule can be formulated as to the age incidence of such growths, 

 since they have been described both in the new-born and in the aged. 

 Such cysts are commonly single, but may be multiple. They are lined 

 with flattened cells and contain fluid which is occasionally discoloured 

 from recent haemorrhage. These cysts are very seldom accompanied by 

 any changes of the pubertas precox type. 



2. Cholesteatomata. — These tumours occur in the region of the pineal ; 

 they are firm in consistency, the cut surface being yellowish-white and 

 waxy in appearance. On section they can be seen to be composed of 

 lamellated waxes or scaly material enclosed in a wall of stratified squamous 

 cells concentrically arranged. Such cells may be multinucleated. The 

 waxy material consists of desquamated cells and cholesterol crystals. 



Cholesteatomata occur anywhere in the brain, but more especially 



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