Tumors of cerebral hemispheres are benign and malignant tumors located directly in the tissues of the brain. Tumors of the cerebral hemispheres are manifested by cerebral (headache, stagnation of the optic nerve discs, dizziness, vomiting, mental disorders) and focal (motor disorders, loss of sensitivity, visual disorders, speech disorders, neuro-endocrine syndrome, etc.) symptoms. Diagnosis of brain hemispheric tumors includes ophthalmoscopy, EEG, Echo-EG, CT and MRI of the brain, stereotactic biopsy. Treatment of a brain hemisphere tumor may include radical or partial removal, surgical decompression of the brain, chemotherapy, radiation therapy and symptomatic treatment.
Tumors of cerebral hemispheres occupy approximately 1.4% of all malignant tumors. They account for 2.4% of all deaths associated with cancer, both in adults and in children. The incidence of brain hemispheric tumors is 3.7 per 100 thousand people. Currently, there is an upward trend in this indicator. Tumors of the cerebral hemispheres in pediatric practice are much less common than in adult patients. The most susceptible to morbidity are people aged 20 to 50 years. Tumors of cerebral hemispheres are the subject of joint study of neurology, oncology and neurosurgery.
The undisputed cause of the development of a brain hemisphere tumor is radiation. This is confirmed by the occurrence of intracerebral tumors in patients undergoing radiation therapy due to various diseases. It is assumed that the risk of a brain hemisphere tumor increases with the use of the sugar substitute aspartame, exposure to vinyl chloride, and the adverse effects of electromagnetic fields when using a mobile phone.
Some authors associate brain hemispheric tumors with disorders in the immune system, which may be congenital, observed in HIV patients or are the result of immunosuppressive therapy. It has also been noted that a number of brain hemispheric tumors are associated with diseases such as tuberous sclerosis, Hippel-Lindau disease, Recklinghausen neurofibromatosis.
The separation of brain hemispheric tumors into primary and secondary (metastatic) is fundamental. Primary tumors of the cerebral hemispheres mostly develop from glial elements, for which they were called glial tumors. Of these, astrocytoma is the most common. There are also primary tumors of the cerebral hemispheres originating in connective tissue structures (for example, in the lining of the cerebral vessels) and glandular tissue. These include sarcomas and angioretyculomas, adenomas.
Metastatic brain tumors are metastases of malignant tumors of extra-cerebral localization. Lung cancer metastasizes to the brain more often than others, breast cancer takes the second place in the frequency of intracerebral metastases. Less often, secondary tumors of the cerebral hemispheres occur with metastases of melanoma, hypernephroma, retinoblastoma, adrenal tumors, etc.
General cerebral symptoms
The general cerebral symptoms of an intracerebral tumor of the cerebral hemispheres are associated with an increase in intracranial pressure (hydrocephalus). Moreover, the degree of hypertension does not directly depend on the size of the tumor. Thus, small tumors of the cerebral hemispheres can lead to impaired cerebrospinal fluid dynamics and a significant increase in intracranial pressure, and large tumors are sometimes accompanied by mild cerebral symptoms. General cerebral symptoms include: headache, dizziness, vomiting, damage to the optic nerve discs, mental disorders, epileptic seizures.
With an intracerebral tumor of the cerebral hemispheres, the headache has a dull bursting diffuse character. In the initial period, it usually occurs periodically, and then becomes permanent. Often, patients note a decrease in the intensity of headache at a certain position of the head (usually in the prone position on the affected side of the head).
A characteristic clinical sign of a brain hemisphere tumor is dizziness. It has a paroxysmal systemic character in the form of a feeling of its own rotation or rotation of surrounding objects. Dizziness may be accompanied by other symptoms of vestibular ataxia, nausea, autonomic disorders, tinnitus. Usually, with a tumor of the cerebral hemispheres, unlike a tumor of the cerebellum, dizziness appears in the later stages of the disease with significant cerebrospinal hypertension.
A distinctive feature of vomiting with a tumor of the cerebral hemispheres is its occurrence outside of connection with food intake; most often in the morning on an empty stomach. Vomiting is also often observed at the peak of a headache. Since vomiting leads to a decrease in headache, some patients specifically cause a gag reflex for this purpose. With tumors of the IV ventricle and cerebellum, vomiting can occur without a headache and be provoked by a change in body position.
The lesion of the optic nerve discs in most cases is bilateral and is caused by the development of stagnant phenomena in them under the influence of constantly increased intracranial pressure. Congestive optic nerve discs are an early symptom of a brain hemisphere tumor and can be detected during ophthalmoscopy during a period when the subjective sensations of patients are still poorly expressed. The lesion of the optic nerves is clinically manifested by the flashing of “flies” in front of the eyes, periodically appearing “fog” in the eyes. At the same time, unlike optic neuritis, visual acuity persists for a long time. Over time, stagnant changes can lead to atrophy of the optic nerve.
Mental disorders are often observed with tumors of the hemispheres of the brain. They can be of a very diverse nature from violations of the mnestic sphere (memory, attention, thinking) and psycho-emotional restructuring of the personality (increased irritability, aggressiveness or, on the contrary, apathy, excessive complacency) to severe mental disorders (hallucinations, delusions, twilight states of consciousness). The gradual progression of mental disorders is characteristic, although with the malignant nature of the tumor of the cerebral hemispheres, this process proceeds quite quickly.
Often brain hemispheric tumors are accompanied by epileptic syndrome. This is most often observed when the process is located in the temporal lobe (temporal lobe epilepsy). There are various types of epi-attacks from small to primary generalized. The nature of the aura preceding the attack often suggests the approximate location of the tumor.
There are primary focal symptoms of a tumor of the cerebral hemispheres, arising from the direct impact of the tumor on the surrounding tissues, and secondary — due to displacement and infringement of brain structures distant from the tumor, ischemia of brain tissues located far from the tumor, but blood supply by vessels squeezed by it.
With a tumor of the cerebral hemispheres localized in the frontal lobe, the frontal syndrome comes to the fore: psychomotor disorders, behavior changes, emotional and volitional spheres. It is characterized by a slowdown in speech and thinking, paresis of the facial nerve of the central type, the occurrence of a grasping reflex, generalized epi-attacks with preceding tonic seizures and violent turning of the eyes and head.
Tumors of the hemispheres of the brain located in the parietal lobe are accompanied by disorders of sensitivity and musculoskeletal feeling, disorders of perception of one’s own body. Tumor lesions in the dominant hemisphere lead to impaired counting, writing (dysgraphy) and reading (dyslexia).
Tumors of the cerebral hemispheres in the temporal lobe are characterized by the early appearance of epi-attacks. Complex auditory and visual hallucinations, unpleasant visceral sensations are possible. Tumors of the left temporal lobe lead to sensory aphasia. The lesion of the posterior temporal divisions proceeds with the development of homonymous hemianopia (loss of the eponymous halves of the visual fields).
Brain hemispheric tumors located in the occipital lobe are manifested by various disorders of visual function: partial or complete hemianopia, visual hallucinations, photopsias and metamorphopsias, optical agnosia.
Tumors of the cerebral hemispheres in the area of the Turkish saddle (for example, pituitary adenomas) are accompanied by neuro-endocrine syndrome. Depending on the age of the patient, the nature and localization of the tumor, acromegaly, gigantism, pituitary nanism, Itsenko-Cushing’s disease may be observed, in women — menstrual cycle disorders, amenorrhea. Tumors of the pineal body in childhood lead to early puberty.
Tumors of the corpus callosum lead to pronounced mental disorders and disorders of orientation in space. Tumors of the cerebral hemispheres in the area of subcortical structures manifest an increase in intracranial pressure and early stagnant changes in the visual discs. Then there are sensitivity disorders, vegetative symptoms (hyperhidrosis, lability of pulse and arterial pressure, difference in skin temperatures of different parts of the body), violent laughter and crying, facial maskiness.
A neurologist can suspect an intracerebral tumor based on the patient’s complaints and the detected violations in the neurological status. Exclusion of brain hemispheric tumors is necessary in all patients with first-time epi-attacks. An examination by an ophthalmologist with the determination of visual acuity, perimetry and ophthalmoscopy is mandatory. In case of hearing disorders, an otolaryngologist’s consultation is prescribed, in the presence of neuro-endocrine syndrome — an endocrinologist, and for women additionally a gynecologist-an endocrinologist.
Tumors of the cerebral hemispheres in most cases are accompanied by significant hydrocephalus detected during Echo-EG. If the tumor causes a displacement of brain structures, then a displacement of echo signals from the midline is detected. With the help of EEG, the presence of epileptic activity is determined. REG with a tumor of the cerebral hemispheres often gives information about certain disorders of intracerebral circulation, which may be associated with reflex vascular spasm or compression of vessels by a growing tumor.
Neuroimaging methods: CT and MRI of the brain are recognized as the best methods of objective detection of brain hemispheric tumors. They make it possible to determine the exact localization of the brain hemisphere tumor and differentiate it from intracerebral hematoma, cyst in syringomyelia, brain abscess, multiple sclerosis, epilepsy. However, only histological examination allows to make a reliable diagnosis and verify tumors of the hemispheres of the brain. It can be performed with brain tissue samples obtained during stereotactic biopsy or intraoperatively.
The main method in the treatment of a brain hemisphere tumor remains its surgical removal. Benign tumors of cerebral hemispheres reaching a size of no more than 3.5 cm can be removed using stereotactic radiosurgery. Unfortunately, removal of glial tumors is often impossible due to their significant germination into the surrounding brain tissue. Complete removal of non-glial tumors is possible only if they are benign in nature. Removal of ventricular tumors presents significant difficulties for neurosurgeons. In cases when it cannot be performed in full, a bypass operation is additionally performed. Removal of metastatic tumors is possible if they are isolated or localized in one area.
With an tumors of cerebral hemispheres, palliative interventions aimed at reducing the degree of hydrocephalus and preventing dislocation of brain structures are possible. These include decompressive trepanation of the skull, external ventricular drainage, ventriculoperitoneal bypass surgery.
Surgical treatment of brain hemispheric tumors is often combined with radiation and chemotherapy. Irradiation is usually carried out in the mode of remote gamma therapy 1-2 weeks after the operation. The conditions for effective chemotherapy are accurate verification of the tumor and determination of the patient’s sensitivity to the chemotherapy drug. Chemotherapy is carried out in courses with mandatory monitoring of blood parameters and accompanying antiemetic therapy. It can be carried out by local administration of drugs into the cerebrospinal fluid system or directly into the tumor bed.
A favorable prognosis is observed in the case of angioretticuloma or adenoma, subject to its radical surgical removal. Glial tumors of the cerebral hemispheres are characterized by frequent recurrence, the duration of postoperative survival of patients with them depends on the degree of malignancy of the tumor.