CHAPTER 34

BRAIN TUMORS AND THE PATHOPHYSIOLOGY OF CEREBRAL NEOPLASMS
By Rhawn Joseph, Ph.D.
Reprinted From: Rhawn Joseph, Neuropsychiatry, Neuropsychology, Clinical Neuroscience (Williams & Wilkins)

By Rhawn Joseph, Ph.D.

In the United states malignant brain tumors are the second most common cause of cancer related death in individuals up to age 34, and the third most comon cause in males up to age 54. Each year over 40,000 patients are diagnosed as having brain tumors (Hill et al., 1999). Among children, 2.5 to 4 per 100,000 become afflicted yearly (Packer, 1999). According to Packer (1999, p. 421), "tumors of the nervous system are the most common form of childhood malignancy and the leading cause of cancer-related morbidity and mortality."

Brain tumors have a number of originating etiologies and may arise following head injury, viral or bacterial infection, metabolic and other systematic diseases, and are associated with exposure to toxins and radiation, as well as genetic abnormalities (Blumenthal, et al., 1999; Hill et al., 1999; Shapiro, 1999). Some are due to tumors that developed in other parts of the body and which metastasized to the brain. Yet others are believed to have originated in embryonic cells left in the brain during development (Burger & Scheithauer, 1994).

In some cases tumors are a consequence of embyrological timing and migration errors. That is, if germ layers differentiate too rapidly or if cells migrate to the wrong location, they exert neoplastic influences within their unnatural environment. These are a primary cause of congenital tumors.

Among children, many tumors are congenital developing from displaced embyronic cells, dysplasia of developing structures, and/or due to the altered development of primitive cells which normally act as precursors to neurons and glia. Most of these "congenital" tumors tend to occur within the brainstem, cerebellum, midline structures, including the third ventricle and cervical-medullary junction (Burger & Scheithauer, 1994; Robertson et al. 1994).

Among older individuals, most tumors are due to dedifferentiation of adult elements. However, in both adults and children, the possibility of environmental factors as causative agents, that is, tumors as due to poisoning of the environment, is seen as increasingly likely.

For example, tthe incidence of tumors have increased over the last two decades (Packer, 1999). Among children the incidence has increased by 35% (Smith et al., 1988). In fact, not just tumors, but an exceedingly high rate of secondary cancers have also been reported, especially among those younger than 3 (Duffner et al., 1998); which again raises the possibility of environmental factors as a causative agent.

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TABLE OF CONTENTS

TUMOR DEVELOPMENT: ONCOGENES & DEFECTIVE DNA EXCISION REPAIR

TELOMERASE, TELOMERES, "IMMORTAL CELLS" & TUMOR GROWTH

THE ESTABLISHMENT & GROWTH OF A TUMOR

VASCULARIZATION & NECROSIS

INVASION & DESSIMATION

METASTASIS

MALIGNANCY

TUMOR GRADING.

AGE FACTORS IN TUMOR DEVELOPMENT

EXTRINSIC & INTRINSIC TUMORS

NEOPLASMS & SYMPTOMS ASSOCIATED WITH TUMOR FORMATION

FAST VS. SLOW GROWING TUMORS

GENERALIZED NEOPLASTIC SYMPTOMS
INCREASED INTRACRANIAL PRESSURE

HEADACHE

SEIZURES

FOCAL SYNDROMES & NEOPLASMS
FRONTAL LOBE TUMORS

TEMPORAL LOBE TUMORS.

PARIETAL LOBE TUMORS.

OCCIPITAL TUMORS.

BRAINSTEM TUMORS.

CEREBELLAR TUMORS.

TUMORS OF THE VENTRICLES: EPENDYMOMAS

MEDULLOBLASTOMA.

TUMORS OF THE PINEAL GLAND: PINEALMOMAS.

MIDBRAIN TUMORS.

PITUITARY TUMORS

TUMORS OF THE MENINGES: MENINGIOMA.

Prognosis & recovery.

ACOUSTIC NEUROMAS & SCHWANNOMAS.

ASTROCYTOMA & GLIOBLASTOMA MULTIFORME ABNORMAL GLIA DEVELOPMENT

ASTROCYTOMAS

TUMOR GRADING

PREFERENTIAL REGIONS OF FORMATION.

MORTALITY & MALIGNANCY.

GLIOMAS

GLIOBLASTOMA MULTIFORME

OLIGODENDROGLIOMA.

LYMPHOMAS, NEUROBLASTOMAS, SARCOMAS, CYSTS LYMPHOMAS

SARCOMAS

NEUROBLASTOMAS

CYSTS

UNILATERAL TUMORS AND BILATERAL DYSFUNCTION

HERNIATION

PROGNOSIS


BRAIN IMAGES

BRAIN TUMORS: MRI & FUNCTIONAL BRAIN IMAGING

STROKE & HEMORRHAGE: MRI & FUNCTIONAL BRAIN IMAGING



The Origins of Life
Table of Contents
Table of Contents


Biological Big Bang

Life On Earth Came From Other Planets



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