Brain Tumours

Overview

Tumors of the central nervous system differ from neoplasms of other localizations in histogenesis, clinical manifestations, and treatment options. The presence of the blood-brain barrier also determines the specificity of tumors, since it limits the penetration of many substances (including drugs) from the blood into the brain tissue. By the nature of the clinical course, all brain tumors are malignant, as they lead to death due to hypertension and dislocation of the brain. There are fast-growing (gliomas, metastases, glioblastomas, adenocarcinomas, etc.) and relatively slow-growing (meningiomas, adenomas, etc.) tumors. 
 In adults, 40-45% of all brain tumors are gliomas, 18-20% are meningiomas, 8% are neurinomas of the VIII nerve, and 6-8% are pituitary adenomas
In childhood, tumors originate from less differentiated cells (medulloblastoma, neuroblastoma, chordoma). In adults, 40-45% of all brain tumors are gliomas, 18-20% are meningiomas, 8% are neurinomas of the VIII nerve, and 6-8% are pituitary adenomas
CLASSIFICATION
In relation to the brain, tumors are divided into intracerebral (from brain cells) and extracerebral (from the meninges, cranial nerves, skull bones, etc.). According to localization, CNS tumors are subdivided into intracranial (90%) and spinal (10%).
According to the WHO histological classification (Kleihues P. et al., 1993), CNS tumors are divided into:
1) tumors from neuroepithelial tissue;
2) nerve tumors;
3) tumors of the meninges;
4) lymphomas 
5) germ cell tumors;
6) cysts and tumor-like lesions;
7) tumors of the Turkish saddle area;
8) tumors growing into the cranial cavity;
9) metastases;
10) unclassified tumors.



Symptoms

Headache is one of the cardinal, frequent and early cerebral symptoms of developing brain tumors. Episodic headache at the beginning of the disease progresses in intensity and becomes permanent with periodic
Tumors of supratentorial localization are accompanied not only by diffuse hypertensive headache, but also by local pain in the homolateral temporal region. In the presence of a tumor in the parietal lobe, headache, on the contrary, appears in the late stage of the disease, is diffuse and inconsistent
Vomiting is an ambivalent symptom of brain tumors, acting in some cases as a general cerebral, in others - as a local symptom. As a cerebral symptom, vomiting is more common and has no topical anatomical significance. Occurs regardless of food intake, often on an empty stomach, without prior nausea, belching and abdominal pain, appearing at the height of a headache, at night or in the early morning hours, often with a change in body position
Irritation of the nuclear formations of the lower part of the bottom of the IV ventricle underlies another, often accompanying isolated vomiting symptom – hiccups
Asymmetric visual disturbances in combination with destruction or hyperostosis of the wings of the sphenoid bone are very characteristic of meningiomas of this localization.
Cerebral edema. Cerebral edema is understood as an excessive accumulation of intercellular fluid in its tissue; an increase in the volume of intracellular fluid is called swelling of the brain. The terms "edema" and "edema-swelling" can be considered unambiguous, because the pathogenetic mechanisms of edema and swelling are basically the same or interrelated.
intracranial hypertension. Normal intracranial pressure during lumbar puncture in the supine position is 150-180 mm of water column.
Dislocations and herniations of the brain. The reasons and mechanisms of their occurrence are partly described above. The most common are lateral temporotentorial and axial occipital herniations.
Cranial Nerve Disorders
I - olfactory nerve. Decreased sense of smell up to anosmia
II - optic nerve III, IV, VI - a group of oculomotor nerves. Violation of the function of this group of nerves can occur due to damage at the radicular level, in particular, with tumors of the cavernous sinus, and is manifested by eye difference, limitation of eye mobility (including in the direction of the affected muscle), doubling, ptosis, impaired pupillary reactions, anisocoria.
V - trigeminal nerve. Dysfunction in the form of symptoms of paresthesia, or prolapse 
VII - facial nerve. Central (supranuclear) paresis is very common and is not of great importance in topical diagnosis

IX, X, XI, XII - caudal group. Symptoms of their radicular lesions are manifested by a violation of phonation, swallowing, taste on
posterior third of the tongue, sensitivity in the oral cavity and pharynx, atrophy of the muscles of the tongue, etc. They occur with large neurinomas of the VIII nerve with a caudal direction of growth, meningiomas of the basal parts of the posterior cranial fossa and other tumors.



Causes

Although few factors are unequivocally associated with an increased risk of brain cancer, most CNS neoplasms are thought to arise from individual cell mutations. A few inherited diseases, such as neurofibromatosis, tuberous sclerosis, multiple endocrine neoplasia (type 1), and retinoblastoma, increase the predilection to develop CNS tumors. Primary CNS lymphoma is a relatively frequent occurrence in HIV patients. A prior history of irradiation to the head for reasons other than treatment of the present tumor may increase the chance of primary brain tumor.
The most common tumors originating from the cerebellopontine angle are acoustic neuroma and meningioma.



Prevention

A brain tumour cannot be prevented, claims Preventions of Brain Tumor. Making more informed judgements can be aided by being aware of the risk factors and talking to your doctor about them. However, there are currently no well-known methods of preventing a brain tumour by a change in lifestyle.
 



Treatment

Surgical treatment of brain tumors
Indications for surgery. In most brain tumors, indications for surgery prevail over indications for other methods of treatment. Nevertheless, the problem of determining indications and contraindications for surgical treatment is complex, and its solution is not always unambiguous.
 In this case, the choice of the type of operation depends on a number of factors: the location and histology of the tumor, the severity of the patient's condition, age, the presence of concomitant diseases, etc. However, in some cases, the operation is not performed even with a direct threat to the life of the patient: mainly in inoperable, deep-seated malignant gliomas (especially in case of recurrence), in elderly patients who are in a terminal state, as well as in cases where the tumor is not available for direct surgery, and palliative intervention is impossible or will not give a positive effect.
Indications for surgery are also considered relative if there is a high probability that it can aggravate the existing defect (for example, with gliomas of the motor, speech, and other functionally important areas).
Operations for brain tumors. There are two requirements for surgical access to the tumor:
- a sufficient overview for an effective operation;
- access should be as sparing as possible in relation to the functionally important parts of the brain.
The most common approach requiring craniotomy. There are 2 types of trepanation - osteoplastic (craniotomy) and resection (cranioectomy).
The main types of operations for brain tumors
Radical removal of the tumor. Total or subtotal removal is possible with most extracerebral tumors (neurinoma, meningioma, pituitary adenoma, etc.), as well as a number of gliomas.
In recent years, the number of such operations has increased significantly due to the introduction of a microsurgical technique for removing a tumor, which includes, in addition to the special training of surgeons, the use of an operating microscope or a binocular loupe combined with a light source, microinstrumentation, bipolar coagulation combined with a laser microscope, ultrasonic suction. At the same time, the preparation of vessels and nerves included in the tumor became possible, as well as its careful separation from vital structures - the walls of the third ventricle, the brain stem, etc
palliative operations are undertaken when direct intervention on the tumor is impossible at all, or, taking into account the patient's condition, it is advisable to postpone it until the secondary symptoms of the tumor (mainly occlusive-hypertensive-hydrocephalic syndrome) are removed.
They include operations on the CSF system - perforation of the fundus of the III ventricle according to Stukki, porencephaly of the lateral ventricle, perforation of the interventricular septum, draining operations (installation of temporary ventricular drainage), ventriculocisternostomy according to Thorkildsen, atrioventricular shunting, etc.
It should be emphasized that in case of occlusion at the level of the foramen of Monro, bilateral drainage is carried out, in case of occlusion of the posterior sections of the third ventricle, the Sylvian aqueduct and the fourth ventricle, one-sided drainage is performed.
Radiation, drug and combined treatment of CNS tumors
Methods of radiation exposure can be divided into radiosurgical and radiotherapeutic. Radiosurgical methods of treatment include: implantation of solid radiopharmaceuticals (usually yttrium) into the tumor tissue, mainly in the skull base tumor. Radiation therapy methods of treatment include remote radiation therapy: X-ray therapy, gamma therapy, irradiation with a beam of protons or other heavy accelerated particles.



Tests Required for Diagnosis

If a brain tumor is suspected, the following are performed:
• A thorough neurological examination, including a detailed ophthalmological examination of acuity, visual fields and fundus; Otoneurologist examines the sense of smell, taste, vestibular functions.
 Craniography in two main projections, which, according to indications, is supplemented by images taken during special laying. Craniography allows you to identify local bone changes - hyperostoses, etc., 
Electroencephalography (EEG) to detect focal symptoms of brain damage and (or) assess violations of the physiological mechanisms of brain activity in general.
•   Echoencephalography (EchoEG). Ultrasound scanning makes it possible to detect large tumors of the hemispheres, especially cystic ones, to determine the displacement of the midline of the brain with a hemispheric localization of the tumor, and also to detect ventricular hydrocephalus.
 Lumbar puncture. It is used to measure pressure and laboratory analysis of cerebrospinal fluid. Currently, it is practically not used as an independent diagnostic procedure for brain tumors
Gammaencephalography (GEG) is a method of radioisotope scanning, which makes it possible to obtain an image of a tumor in the form of a focus of isotope accumulation
• X-ray CT and MRI are the most informative modern diagnostic methods
Cerebral angiography  gives an x-ray image of the vessels of the brain when a contrast agent is injected into the arterial bed. For supratentorial tumors, carotid angiography is used, for subtentorial tumors, vertebral angiography is used.
 Pneumoencephalography. It is based on the contrasting of the cerebrospinal fluid spaces of the brain with air introduced endolumbally. Currently, it is practically not used.  



Disclaimer

The information provided in this article is for general informational purposes only. It is not intended as a substitute for professional medical advice, diagnosis or treatment. For any concerns about your health or you are experiencing symptoms, it is important to consult with a healthcare professional. They will be able to assess your specific situation and provide you with personalised advice and treatment based on your symptoms, body type, allergies (if any), existing medical conditions etc. It is always better to consult with a healthcare professional before making any decisions about your health. By accessing this article you agree with our terms and condition https://proceed.fit/frontend/terms_conditions.