Book - The Pineal Organ (1940) 29
Embryology - 23 Apr 2024    Expand to Translate
|
|---|
| Google Translate - select your language from the list shown below (this will open a new external page) |
|
العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt These external translations are automated and may not be accurate. (More? About Translations) |
Gladstone RJ. and Wakeley C. The Pineal Organ. (1940) Bailliere, Tindall & Cox, London. PDF
| Historic Disclaimer - information about historic embryology pages |
|---|
 |
The Pineal Organ
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 hypertrophy. 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 do they occur near the midline. They are regularly connected with the meninges. Bostroem concludes that all cholesteatomata arise from embryonal epidermal inclusions.
3. Teratomata. — These tumours arise exclusively in young males from 4 to 16 years of age, and are associated with precocious sexual development, hirsutes, and sometimes with adiposity and general overgrowth.
These complex teratcmata are of moderate size ; they may be solid or cystic, and are usually circumscribed. They give rise to marked pressure signs. They may consist almost entirely of hair, sebaceous material, epidermoid cysts, cartilage, calcific grains, fat tissue and non-medullated nerve-fibres, and smooth muscle. l A small layer of normal pineal tissue may be found beside and unusually compressed and displaced by the tumour. They are firm in consistency, irregular and knobbly on the surface, often with elongated shreds of tela choroidea adherent to the upper and posterior surface.
Their nature and origin is obscure, but of interest ; they are probably derived from embryonic vestiges. The dermal structures, such as hair and sebaceous glands, require an ectodermal tissue for their development, which may possibly reach the pineal gland by the same developmental disturbances that give rise to cholesteatomata. It must also be remembered that in certain reptiles and fishes the pineal is a well-developed organ which passes through a minute foramen in the skull and reaches the surface. Alternatively these may develop by pseudogestation from a fertilized filial polar body.
4, 5. Pinealomata and Pineoblastomata. — Tumours arising from the pineal gland tend to resemble the structure of the developing pineal at some definite stage of its development. The more primitive the type that is found in these tumours, the more rapidly growing and more invasive is the growth. The primitive type of such tumours is termed pineoblastoma. The course is usually short. If the tumour cells resemble more the adult type of pineal structure, they are slow growing, less invasive, are less liable to haemorrhage, and less vascular, and the tumour is termed pinealoma.
Pineoblastomata : these tumours are usually soft, with a tendency to infiltrate into the surrounding tissue — the hemispheres, the cerebellum, and the third ventricle — and tend to obliterate the aqueduct. Cysts are often present and areas of haemorrhage occur. The surface is irregular and lobulated ; cysts may be seen on the cut surface.
1 Transversely striated muscle fibres have also been found in teratomata of the pineal gland, and very occasionally in the normal gland, more especially in the ox, as described by Nicolas and Dimitrowa (Fig. 284;. Striated muscles fibres have, moreover, been observed by Hammer in the epiphysis of a human foetus aged 5 months, and cells which have been described as "myoid" in the adult human organ. They have been found chiefly in the vascular connective tissue septa or trabecular, and usually appear as isolated fibres, as in the specimen described by Dimitrowa. In some cases the nucleus is central and the general appearance of the fibres is intermediate between that of the striped and unstriped types of muscle-fibres.
Microscopically there is a marked variation in the type and arrangement of cell found. The cells are arranged in a mosaic with streams of small cells deeply staining in character and enclosing nests of larger cells with vesicular nuclei and larger masses of clear cytoplasm, bearing a strong resemblance to the parenchyma cells of the mature pineal body. Giant cells are not an uncommon feature in various areas of these tumours ; they are more common in the vicinity of the calcified plaques, which are a frequent feature of such growths.
Fig. 284. — A Transversely Striated Muscle-Fibre from the Epiphysis of Bos taurus. (After Dimitrowa.)
Pinealomata : the other main type is that which more closely approximates to the adult or mature type of pineal. They are slower in growth and less invasive. Haemorrhages and cysts are less common. Microscopical section shows an alveolar pattern ; the cells are chiefly of the large vesicular type, and are separated by strands of fibrous tissue.
Thus we see the importance of recognizing the developmental stages through which the pineal passes when attempting to understand the histology of these tumours.
Fig. 285. — Section through Pineal Body showing a Central Cavity, the Wall of which is stained deeply and contains numerous Corpora Arenacea.
Art. : artery.
Cav. : central cavity.
C. Ar. : corpora arenacea.
c.t. cap. : connective tissue capsule.
Ep. : ependyma.
gl. sh. : glial sheath.
Pig. : pigment.
P.M. : pia mater.
Ps. Ep. : pseudo-epithelium.
V. : vein.
ves. : vessel.
(Drawn from a specimen in Professor Barclay-Smith's collection at King's College, London.)
General Changes. — The associated changes in the brain are due to direct displacement and invasion of the brain substance. The cerebellum is often invaded. The growth extends beneath the tentorium and invades the cerebellum both in the midline and in either of the lateral lobes.
The midbrain is pressed upon, and especially the corpora quadrigemina. This distortion gives rise to the characteristic eye signs and may also occlude the aqueduct of Sylvius. Occlusion of the aqueduct may also be brought about by direct invasion of the third ventricle by the growth. The outcome of these changes is that the whole ventricular system above the aqueduct becomes distended and internal hydrocephalus results. Pressure on the vein of Galen by the growth may also play a part in the development of the hydrocephalus.
The floor of the third ventricle is depressed. The hypophysis is pressed upon and the hypothalamus distorted. It is this change as well as the direct invasion which occurs which probably accounts for the changes in growth and sexual development and other hypothalamic signs which are sometimes seen. Extension may occur into the cerebral hemispheres by direct invasion.
Haemorrhage occurs into these growths, and terminally haemorrhage into the ventricles is not an uncommon finding. Changes are also found around the medulla, there usually being a very well-developed pressure cone.
| Historic Disclaimer - information about historic embryology pages |
|---|
|
Cite this page: Hill, M.A. (2024, April 23) Embryology Book - The Pineal Organ (1940) 29. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_The_Pineal_Organ_(1940)_29
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
