Benign brain tumors

Definition

A brain tumor, also known as an intracranial tumor, is an abnormal mass of tissue in which cells grow and multiply uncontrollably. They arise from the bone tissue of the skull, brain membranes, cranial nerves, brain parenchyma, pituitary gland, and others. 

Primary brain tumors are most often localized in the posterior cranial fossa in children and the anterior two-thirds of the cerebral hemispheres in adults, although they can affect any part of the brain. Primary intracranial tumors are divided into glial (consisting of glial cells, which form the medium of neurons and provide nutrients and oxygen to nerve tissue) and non-glial (developing in brain structures, including nerves, blood vessels, and glands).

Benign tumors have clear boundaries or are encapsulated, characterized by slow growth.

Benign tumors do not grow into adjacent tissues and organs and do not metastasize. However, when localized in a vital part of the brain, they compress sensitive nerve tissues and cause an increase in intracranial pressure. Such neoplasms can be removed, after which they usually do not recur.

Causes of benign brain tumors

The cause of most benign brain tumors is unknown, but the likelihood of developing one is higher when several riskfactors are present:

• Environmental exposures – occupational hazards, chemicals, ionizing radiation, exposure to therapeutic X-rays, and chemotherapy.
• Genetic diseases, including neurofibromatosis, tuberous sclerosis, Burneville’s disease, Li-Fraumeni, vonHippel-Lindau, Turcotte syndromes, and other hereditary pathologies. 

Infections, degenerative processes, and autoimmune processes can damage brain structures. Decreased immunity increases the risk of certain tumors. Immunodeficiency can be congenital or acquired. Brain injuries and concussions can trigger a tumor in any part of the brain.

Classification of the disease

There are many different types of benign brain tumors, which are related to the type of brain cells affected:

• gliomas are a common type of tumor that arise from glial cells that hold and support nerve cells and fibers;
• meningiomas arise in the cerebral membranes, the three outer layers of tissue that cover and protect the brain just beneath the skull. They account for more than 30% of all brain tumors;
• acoustic neurinomas are tumors of the auditory nerve that connect the ear to the brain and help with balance (also known as vestibular schwannomas). They usually develop in middle-aged adults and often cause hearing loss;
• pituitary adenomas – pea-sized tumors on the lower surface of the brain. Some of them produce hormones and can cause vision problems and endocrinologic disorders;
• craniopharyngiomas are tumors near the base of the brain that are most often diagnosed in children, adolescents, and young adults. Craniopharyngiomas usually arise from part of the pituitary gland (a structure that regulates many hormones in the body) and may appear as solid tumors or cysts;
• hemangioblastomas are tumors of blood vessels, usually located in the cerebellum. They can be large and are often accompanied by the formation of cysts. They most often occur in children under two years of age and, in some cases, cause hydrocephalus, which can lead to increased intracranial pressure and increased skull size;
• neurofibromas are soft growths that develop in the brain, cranial nerves, and spinal cord. Multiple neurofibromas are considered a symptom of the genetic disease neurofibromatosis type 1.

Symptoms

Symptoms of a benign brain tumor depend on how large it is and where it is localized in the brain. Some slow-growing tumors may not cause any symptoms at first.

Common symptoms are similar to those of many other diseases and include:

• persistent severe headaches (the most common symptom);
• mental or behavioral changes, personality changes (lack of initiative, slovenliness, mood swings, with the progression of the disease increases aggressiveness, negativism);
• constant malaise, nausea, or vomiting against the background of headache, difficulty swallowing;
• seizure syndrome, epileptic seizures;
• loss of balance or sudden dizziness;
• decreased reflexes in the limbs, muscle weakness (paresis);
• all kinds of sensory disturbances;
• transient blurring of vision or “flies” in front of the eyes, with tumor progression, increasing deterioration of vision (optic nerve atrophy), and often a loss of visual fields.

Other symptoms may include hearing, smell, speech, writing problems, gait changes, paralysis of one side of the body, muscle weakness on one side of the face, oculomotor disorders, decreased mental ability, hallucinations, and memory loss.

Focal symptoms depend on the localization of the tumor. Paralysis and seizures are characteristic of frontal lobe lesions, while vision loss and hallucinations are characteristic of occipital lobes. Cerebellar lesions lead to disorders of fine motor skills and coordination and a tumor in the temporal lobe – to hearing loss, memory loss, and epilepsy. Tumors in the hypothalamus or pituitary gland can cause hormonal disorders (Cushing’s disease, acromegaly), impotence in men, menstrual disorders, and decreased libido in women.

Diagnosis of benign brain tumors

Laboratory Diagnostics:

• general blood test;
• urinalysis;
• blood biochemical test;
• blood test for tumor markers: neuron-specific enolase, protein S100.

Instrumental methods of diagnosis:

• Computed tomography and/or MRI of the brain and skull.
• Electroencephalography determines the presence of tumors and foci of seizure activity in the cerebral cortex.
• Ultrasound, in combination with Dopplerography, allows you to see the movement of blood flow.
• Cerebral contrast angiography is an X-ray examination of the brain’s blood vessels.
• Scintigraphy is a modern radiation diagnostics method used to assess the functioning of various organs and tissues.
• Positron emission tomography is based on the intravenous administration of a radioactive indicator, which helps to determine at the molecular level the presence of a pathological process in organs and tissues.
• Histologic examination of biopsy material will help to understand whether it is a benign or malignant neoplasm.

Treatment of benign brain tumors

Surgery is used to remove most benign brain tumors, and they usually do not recur after removal. In some cases, chemotherapy or radiation therapy may be used in addition to the main treatment.

Stereotactic radiosurgery (cyber-knife or gamma-knife) is often used, a method of radiation therapy that allows a large dose of radiation to be delivered to the tumor using neuronavigation without much radiation exposure to healthy tissues. As a result of the radiation, the tumor cells are killed. The effectiveness is comparable to surgical treatment. It is possible to treat neoplasms of hard-to-reach localization. Radiosurgery is effective in treating benign tumors such as meningiomas and neurinomas of the auditory nerve.

Endoscopic interventions are used in the presence of cysts and hematomas after head injuries.

They are minimally invasive operations using a unique endoscopic technique that avoids traumatizing small blood vessels and nerves. These treatments can remove fluid from the ventricles of the brain in children with hydrocephalus (ventriculoscopy). Transnasal removal of pituitary adenoma, when an endoscope is inserted through the sinuses, is one variant of such intervention.

All these treatment options are available in more than 790 hospitals worldwide (https://doctor.global/results/diseases/benign-brain-tumor). For example, Brain tumors surgery can be done in 30 clinics across Turkey for an approximate price of $11.3 K (https://doctor.global/results/asia/turkey/all-cities/all-specializations/procedures/brain-tumors-surgery). 

Complications

The growth of benign tumors is limited to the space of the skull, so when they compress brain tissue, they can cause severe neurological dysfunction and even death.

Neurologic deficits can result from the following causes:

• of increased intracranial pressure;
• bleeding inside or outside the tumor;
• cerebral edema;
• cerebral circulatory disorders.

Prevention of benign brain tumors

Primary prevention of brain tumors:

• physical activity – 30 minutes of daily exercise is enough to keep you healthy;
• healthy night’s sleep helps strengthen the immune system;
• quitting alcohol and smoking;
• walking in the fresh air provides oxygenation of tissues and nerve cell regeneration.