Tumors of the brain
Tumors of the brain — a heterogeneous group of various intracranial neoplasms, benign or malignant, arising from the initiation of an abnormal uncontrolled cell division process, which in the past were normal components of the brain tissue itself (neurons, glial cells, astrocytes, oligodendrocytes, ependymal cells), lymphatic tissue, blood vessels of the brain, cranial nerves, cerebral membranes, skull, glandular structures of the brain (pituitary and epiphysis), or arising from metastasis of tumor located in another organ.
The type of tumor is determined by the cells that form it. Depending on the location and the histological variant, the symptoms of the disease are formed.
Tumors of the brain can be divided into groups according to the following signs:
- By primary hearth
- Primary tumors are tumors that develop from the tissues of the brain, its membranes and cranial nerves (glioblastoma, glioma).
- Secondary tumors are tumors of metastatic origin.
- By cellular composition
The modern histological classification of tumors of the central nervous system developed by WHO experts in 2007 is positively different from previous versions of 1979, 1993, and 2000. First and foremost, the changes in the views on histogenesis and the degree of malignancy of a number of neoplasms that resulted from the widespread use of a number of new techniques in neuromorphology, in particular immunohistochemistry and molecular genetic analysis, were fairly fully reflected in it. It describes more than 100 different histological subtypes of CNS tumors, united into 12 categories. The most common morphological subtypes are listed below:
- Neuroepithelial tumors (ependymoma, glioma, astrocytoma). Develop directly from the brain tissue. They make up about 60%.
- Thoracic tumors (meningioma). Develop from the tissues of the meninges.
- Tumors of the pituitary gland (pituitary adenoma). Formed from the pituitary cells.
- Tumors of the cranial nerves (neurinomas). Occur along the cranial nerves.
- Metastases from the extracerebral focuses. They enter the brain from other focuses by metastasis.
- Dysembryogenetic tumors. Occur in the process of embryogenesis. A rare but serious type of pathology.
The clinical manifestations of brain tumors are determined by their location in a limited volume of the cranial cavity. The compression or destruction of brain tissue in the area of the tumor (due to the germination of the neoplasm) causes the so-called primaryю, or focal, symptomatology. As the disease progresses, there is a so-called cerebral symptomatology, caused by a violation of hemodynamics and intracranial hypertension.
Diagnosis, due to the localization of the tumor inside the skull, is difficult. The diagnosis of cancer is finally put only after a histological conclusion, without a histology or cytology the diagnosis is not legal. Due to the fact that the tumor is located in the cranial cavity and sprouts into the brain tissue, the biopsy sampling is a complicated neurosurgical operation. The diagnosis “brain tumor” is set up in stages – first out-patient, then confirmed in the hospital. There are three stages in the diagnosis.
The patient arrives, as a rule, to the therapist (less often to a neurologist or a doctor of another specialty). Applying the patient forces the progression of focal or cerebral symptoms – while the clinic is poorly expressed, patients rarely get into the field of vision of doctors, and only when the situation begins to deteriorate rapidly, a person turns to a specialist for help.
The doctor assesses the condition of the patient and, depending on his severity, makes a decision about hospitalization or outpatient treatment. The criterion for assessing the severity of a condition is the presence and severity of focal and general cerebral symptoms, as well as the presence and severity of concomitant diseases. If a patient finds a neurological symptomatology, he is sent for consultation to a neurologist. When epileptic fit or convulsion fit occurs for the first time, computed tomography of the brain must be performed to detect oncological pathology.
The neurologist assesses the severity of the symptoms and produces differential diagnosis. His task is to put at least a preliminary, and after a pre-examination, a clinical diagnosis. The doctor, on the basis of the patient’s complaints and the methods of examination available to him, must decide on what diseases he should think about, what instrumental and laboratory methods of examination should be assigned.
The mandatory methods of examination include the determination of activity of tendon reflexes, testing of tactile and pain sensitivity. Diagnostic measures can be extended depending on the patient’s complaints and for the purpose of differential diagnosis. So, for example, if the patient observes a lack of coordination, a finger-nasal test should be performed, and the stability in the Romberg pose should be checked. If there is a suspicion of a brain tumor, the patient is referred to a computer (CT) or magnetic resonance imaging (MRI). MRI with contrast enhancement is the “gold standard” in the diagnosis of brain tumors. If a volume formation is found on the tomogram, the question of hospitalization of the patient in a specialized hospital is decided.
After admission to the oncological dispensary, a number of examinations are conducted to decide the question of the tactics of treatment of this patient, whether he needs surgical intervention and, if necessary, how he will transfer it, whether his inpatient treatment is appropriate. A repeated CT scan or MRI of the brain is performed. The regimens and doses of radiation and chemotherapy are determined, the tumor is mapped, its boundaries, sizes, exact localization are determined. If the patient is assigned surgical treatment, then a tumor biopsy is taken and her histological verification is performed in order to select the optimal regimen for subsequent therapy. Also, a tumor tissue preparation can be obtained by stereotactic biopsy.
Surgical treatment of tumors of the brain and spinal cord is the main, most effective method, however, removal of the tumor from brain tissue is a significant difficulty. Each such intervention is a complicated neurosurgical operation. Since a surgeon needs to excise a tumor within healthy tissues (to avoid relapse), each such operation is traumatic, and often even impossible at all because of the large size of the tumor or its localization in vital parts of the brain. Depending on the size, location, type of tumor, the patient’s condition, a decision is made about the need for the operation, the amount of surgical intervention and the method of its conduct. The use of modern laser and ultrasound technology in the surgery of brain tumors has made it possible to increase its effectiveness somewhat. The specific route of intervention and the method of its implementation is individual and depends on the location of the tumor, its size and cellular composition.