CNS tumors are various neoplasms of the spinal cord and brain, their membranes, cerebrospinal tract, vessels. The symptoms of a CNS tumor have a very variable character and are divided into focal (neurological deficit), cerebral, manifestations in the neighborhood and remote. In diagnostics, in addition to neurological examination, X-ray, electrophysiological, ultrasound methods and cerebrospinal puncture are used. However, more accurate verification of the diagnosis is achieved by MRI or CT, histological analysis of the tumor. In relation to CNS tumors, surgical treatment is most effective. It is possible to use chemo- and radiotherapy as an additional or palliative treatment.
General information
According to various data, CNS tumors occur with a frequency of 2-6 cases per 100 thousand people. Of these, approximately 88% are cerebral tumors and only 12% are spinal. Young people are most susceptible to morbidity. In the structure of pediatric oncology, CNS tumors occupy 20%, and 95% of them are brain tumors. Recent years have been characterized by a tendency to increase morbidity among older people.
Neoplasms of the central nervous system do not quite fit into the generally accepted interpretation of the concept of benign tumors. The limited space of the spinal canal and the cranial cavity cause the compressive effect of tumors of this localization, regardless of the degree of their malignancy, on the spinal cord and brain. Thus, as they grow, even benign tumors lead to the development of severe neurological deficits and the death of the patient.
Causes
To date, the factors that initiate the tumor transformation of cells remain the subject of study. The oncogenic effect of radioactive radiation, some infectious agents (herpes virus, HPV, certain types of adenoviruses), chemical compounds is known. The influence of dysontogenetic aspects of the occurrence of tumors is being studied. The genetic determinant is indicated by the presence of hereditary syndromes of tumor lesions of the central nervous system. For example, Recklinghausen’s neurofibromatosis, tuberous sclerosis, Hippel-Lindau disease, Gorlin-Goltz syndrome, Turko syndrome.
Traumatic brain injuries, spinal cord injuries, viral infections, occupational hazards, hormonal shifts are considered factors that provoke or accelerate tumor growth. A number of studies have confirmed that ordinary electromagnetic waves, including those coming from computers and mobile phones, do not belong to the above triggers. There was an increased incidence of CNS tumors in children with congenital immunodeficiency, Louis-Bar syndrome.
Classification
In accordance with histiogenesis, 7 groups of tumors are distinguished in neurology and neuro-oncology.
- Neuroectodermal tumors: gliomas (benign and dedifferentiated astrocytomas, oligodendrogliomas, ependymomas, glioblastomas), medulloblastomas, pinealomas and pineoblastomas, choroid papillomas, neurinomas, ganglionic cell tumors (gangliocytomas, ganglioneuromas, gangliogliomas, ganglioneuroblastomas)
- Mesenchymal tumors of the central nervous system: meningioma, meningial sarcoma, intracerebral sarcoma, hemangioblastoma, neurofibroma, angioma, lipoma
- Pituitary adenomas
- Tumors from the rudiments of the pituitary gland — craniopharyngiomas
- Heterotopic ectodermal neoplasms (cholesteatomas, dermoid cysts)
- CNS teratomas (extremely rare)
- Metastatic CNS tumors.
It is able to metastasize to the central nervous system
- lung cancer
- chorioncarcinoma
- breast cancer
- renal cell carcinoma
- hypernephroma
- hepatocellular carcinoma
- stomach cancer
- melanoma
- thyroid cancer
- malignant tumors of the adrenal glands, etc.
According to the WHO classification, there are 4 degrees of malignancy of CNS tumors. Grade I corresponds to benign tumors. I-II degrees belong to the low class of malignancy (Low grade), III-IV degrees — to the high (High grade).
Symptoms
It is generally accepted to divide the symptoms of the tumor process of the central nervous system into cerebral, focal, distant symptoms and symptoms in the neighborhood.
Cerebral manifestations are characteristic of cerebral and craniospinal tumors. They are caused by impaired cerebrospinal fluid circulation and hydrocephalus, edema of brain tissue, vascular disorders resulting from compression of arteries and veins, disorder of cortical-subcortical connections. The leading cerebral symptom is cephalgia (headache). It has a bursting, at first periodic, then permanent, character. Often accompanied by nausea. At the peak of cephalgia, vomiting often occurs. The disorder of higher nervous activity is manifested by distraction, inhibition, forgetfulness. Irritation of the meninges can lead to the appearance of symptoms typical of their inflammation — meningitis. Epiprimes may occur.
Focal symptoms are associated with damage to the brain tissue at the site of localization of the neoplasm. They can presumably be used to judge the location of the central nervous system tumor. Focal symptoms are so-called “neurological deficit”, i.e. a decrease or absence of a certain motor or sensory function in a particular area of the body. These include paresis and paralysis, pelvic disorders, hypesthesia, disorders of muscle tone, violations of the statics and dynamics of the motor act, signs of dysfunction of the cranial nerves, dysarthria, visual and hearing disorders unrelated to the pathology of the peripheral analyzer.
Symptoms in the neighborhood appear when the tumor squeezes nearby tissues. An example is the radicular syndrome, which occurs with enveloped or intramedullary tumors of the spinal cord.
Long-term symptoms occur due to the displacement of cerebral structures and compression of brain areas remote from the location of the tumor.
More detailed information about the symptoms of CNS tumors of various localization can be found in the articles:
- Intracerebral tumors of the cerebral hemispheres
- Tumors of the cerebellum
- Tumor of the epiphysis
- Brain stem tumors
- Spinal cord tumors
Phases
The onset of clinical manifestations of CNS neoplasms and the development of symptoms over time can vary significantly. Nevertheless, there are several main types of their flow. Thus, with the gradual onset and development of focal symptoms, they speak of a tumorous course, with the manifestation of a tumor from an epiprime — of an epileptiform course. Acute onset by the type of cerebral or spinal stroke, refers to the vascular type of tumor course, occurs with hemorrhage in the neoplasm tissue. The inflammatory course is characterized by a gradual unfolding of symptoms by the type of inflammatory myelopathy or meningoencephalitis. In some cases, isolated intracranial hypertension is observed.
During the course of CNS tumors , several phases are distinguished:
- Phase 1 of compensation is accompanied only by asthenia and emotional disorders (irritability, lability). Focal and cerebral symptoms are practically not determined.
- Phase 2 of subcompensation is characterized by general cerebral manifestations, mainly in the form of moderate headaches, symptoms of irritation — epileptic seizures, hyperpathy, paresthesia, hallucinatory phenomena. The ability to work is partially impaired. Neurological deficit is expressed to a mild degree and is often defined as a certain asymmetry of muscle strength, reflexes and sensitivity in comparison with the opposite side. Ophthalmoscopy may reveal the initial signs of stagnant optic nerve discs. The diagnosis of a CNS tumor in this phase is considered timely.
- Phase 3 of moderate decompensation is characterized by an average severe condition of the patient with a pronounced disability and a decrease in household adaptation. There is an increase in symptoms, the prevalence of neurological deficit over the symptoms of irritation.
- 4 In the phase of gross decompensation, patients do not leave the bed. There is a deep neurological deficit, disorders of consciousness, cardiac and respiratory activity, distant symptoms. Diagnosis in this phase is overdue. The terminal phase is an irreversible disruption of the activity of the main body systems. There are disorders of consciousness up to coma. Possible brain edema, dislocation syndrome, hemorrhage into the tumor. Death may occur after a few hours or days.
Diagnostics
A thorough examination by a neurologist and anamnesis collection allows us to assume the presence of a voluminous formation of the central nervous system. If a cerebral pathology is suspected, the patient is referred to an ophthalmologist, where he undergoes a comprehensive examination of visual function: ophthalmoscopy, perimetry, visual acuity determination. General clinical laboratory tests are carried out, with the assumption of pituitary adenoma — determination of the level of pituitary hormones. Indirect data on the presence of a brain or spinal cord tumor can be obtained as a result of EEG, Echo-EG and radiography of the spine, respectively. Lumbar puncture allows you to judge the state of cerebrospinal fluid dynamics. In the study of cerebrospinal fluid, pronounced hyperalbuminosis indicates in favor of the tumor, tumor cells are not always detected.
The widespread introduction of neuroimaging methods into practical neurology has opened up significantly greater opportunities for the diagnosis of CNS tumors of any localization. It should be borne in mind that the soft tissue structures of the spinal canal are better visualized during MRI of the spine than with CT of the spine. For the diagnosis of CNS tumors of cerebral localization, it is preferable to conduct an MRI of the brain with contrast. According to the appointment of a neurosurgeon, spinal or cerebral angiography, MR angiography can additionally be performed.
The diagnostic search for a CNS tumor also includes a comprehensive examination of the patient to identify distant metastases or primary tumors. For this purpose, it is possible to conduct:
- MSCT of abdominal organs
- CT of the adrenal glands
- Ultrasound of the thyroid gland
- gynecological ultrasound
- mammography
- radiographs of the lungs
- skeletal scintigraphy, etc.
Stereotactic biopsy of a cerebral tumor and puncture biopsy of a spinal tumor are performed only if absolutely necessary, if it is impossible to accurately diagnose the tumor according to neuroimaging studies. In most cases, a biopsy of a CNS tumor and its histological analysis are performed intraoperatively.
Treatment
The main method of treating CNS tumors is surgical. Operations for cerebral tumors can be performed by trepanation of the skull or transnasally. There is also a method of stereotactic radiosurgery of brain tumors. Operations for spinal tumors include:
- removal of meningioma
- removal of a neurinoma
- removal of ependym
Removal of intramedullary tumors of the spinal cord and cerebral tumors localized in vital structures (for example, in the brain stem) in most cases is not possible due to the damage of the brain substance associated with the operation. According to the indications, palliative interventions are performed: partial resection of the central nervous system tumor, external ventricular drainage, decompression of the spinal canal.
Radiation exposure and chemotherapy can be used as palliative, as well as preoperative and adjuvant treatment. Depending on the type of neoplasm, its prevalence and location, a combination, dose, duration of the course and frequency of treatment are selected. Symptomatic therapy is carried out in parallel.
Forecast
The prognosis of a CNS neoplasm largely depends on the degree of its malignancy, size, nature of growth, prevalence, location and clinical phase in which the diagnosis was made. Due to their characteristics, any tumors of the central nervous system sooner or later lead to a severe and life-threatening condition of the patient. Benign tumors can grow slowly subclinically for more than a decade. Malignant neoplasms often lead to rapid decompensation and death of the patient within 1-2 years.
