A brain tumor or intracranial neoplasm occurs when abnormal cells form within the brain. There are two main types of tumors: malignant or cancerous tumors and benign tumors.Cancerous tumors can be divided into primary tumors that start within the brain, and secondary tumors that have spread from somewhere else, known as brain metastasis tumors. This article deals mainly with tumors that start within the brain. All types of brain tumors may produce symptoms that vary depending on the part of the brain involved
Symptoms as consequences of increased intracranial pressure (often first noticed) Large tumors or tumors with extensive peritumoral swelling (edema) inevitably lead to elevated intracranial pressure which translates clinically into headaches, vomiting (with or without nausea), altered state of consciousness (somnolence, coma), dilation of the pupil on the side of the lesion (anisocoria), papilledema (prominent optic disc at the funduscopic eye examination). However, even small tumors obstructing the passage of cerebrospinal fluid (CSF) can also present such symptoms. Increased intracranial pressure may result in brain herniation (i.e. displacement) of certain parts of the brain, such as the cerebellar tonsils or the temporal uncus, resulting in lethal brainstem compression. In very young children, elevated intracranial pressure may cause an increase in the diameter of the skull and bulging of the fontanelles.
There were 1031 newly-diagnosed cases of spinal/intracranial tumours, 759 of which were primary tumours. The estimated annual incidence of spinal/intracranial tumours was 14.7 per 100 000. The annual incidence of primary CNS tumours was 10.8 per 100 000, and 3.5 per 100 000 for meningiomas. A total of 70 high-grade gliomas (incidence rate of /100 000) and 171 pituitary tumours were diagnosed, both of which were more prevalent in the 45–64-year age group. Meningiomas and pituitary tumours were more common in females. In paediatric patients, there were 36 cases of newly-diagnosed brain tumours, glioma being the most common.