Brain tumours in man

Abstract

Brain tumours occur at all ages but they differ in type depending upon the age of the patient. In adults, probably more than 50% of tumours in the brain are metastatic carcinomas or melanomas. The pathological classification of primary brain tumours depends largely upon the cell type involved. Recently, immunocytochemical identification of cell-specific proteins by the use of polyclonal or monoclonal antibodies has greatly enhanced the accuracy of cell identification within tumours. Primary brain tumours in children arise mainly in the brain stem and cerebellum and are astrocytomas, primitive neuroectodermal tumours (medulloblastomas) and ependymomas. Gliomas form the largest group of primary brain tumours in adults, with an annual incidence of 3.94/100,000 in Southern England. In young adults, well differentiated astrocytomas and oligodendrogliomas arise in the cerebral hemispheres. Poorly differentiated, malignant glial tumours include anaplastic astrocytomas and glioblastoma multiforme; these tumours are most common in older adults with a peak annual incidence of 7.3/100,000 in the sixth decade. The major complication of brain tumours is due to their mass effect from tumour growth and from peritumoral oedema. Surgical excision of gliomas is difficult and usually incomplete due to the infiltrative nature of the tumour. As yet these tumours respond poorly to irradiation and chemotherapy.