Symptoms and types of astrocytomas of the brain

Brain astrocytoma is a tumor that cannot be seen with the naked eye. However, tumor growth does not pass without a trace, because squeezing nearby tissues and structures impairs their functioning, the tumor destroys healthy tissues, and can affect the blood supply and nutrition of the brain. This development is characteristic of any tumor, regardless of its location.

The growth and pressure of the tumor on the vessels of the brain provokes an increase in intracranial pressure, which gives symptoms of hypertensive-hydrocephalic syndrome. They may be joined by signs of intoxication of the body, which is more characteristic of the breakdown of malignant tumors in the advanced stages of cancer. In addition, the tumor irritates sensitive neurons in the brain tissue.

All of the above will result in the appearance of a characteristic symptom complex. A person may have all or some symptoms:

• stable headaches, which are most often aching,
• symptoms of the digestive system in the form of impaired appetite, nausea, and sometimes vomiting,
• visual impairment (double vision, feeling that everything is in a mist)
• unexplained weakness and fatigue characteristic of asthenic syndrome, possible body aches,
• coordination of movements is often noted (the functioning of the vestibular apparatus is impaired).

Some patients even have small epileptic seizures before the tumor is detected. Epiprips with astrocytomas are not considered a specific symptom, because they are characteristic of all brain tumors. However, the cause of the occurrence of seizures without epilepsy in history is quite understandable. The tumor irritates the nerve cells, causing and supporting the process of excitation. It is focal anomalous excitation of several neurons and lead to epileptic seizures, often accompanied by convulsions, short-term loss of consciousness, drooling, about which a person does not remember anything after a couple of minutes.

It can be assumed that the larger the tumor, the greater the number of neurons it can excite, and the harder and more pronounced the attack will be.

So far we have been talking about astrocytoma of the brain, as such, without focusing on the localization of the tumor. However, the location of the tumor also leaves its mark on the clinical picture of the disease. Depending on which part of the brain is affected (pressure) of the tumor, other symptoms appear that can be considered as the first signs of the tumor process of a specific location.[1]

For example, the cerebellum is an organ responsible for coordination of movements, regulation of body balance and muscle tone. It distinguishes between two hemispheres and a median part (a worm, considered phylogenetically older formation than cerebellar hemispheres, which appeared as a result of evolution).

Cerebellar astrocytoma is a tumor formed in one of the parts of this part of the brain. It is the worm that performs the bulk of the work, if we are talking about the regulation of tone, posture, balance, friendly movements that help maintain balance when walking. The astrocytoma of the cerebellum worm disrupts the functioning of the organ, hence the predominance of such symptoms as impaired standing and walking, characteristic of static-locomotor ataxia.[2], [3]

Astrocytomas formed in the frontal lobe of the brain are characterized by other symptoms. Moreover, the clinical picture will also depend on the damaged side, taking into account which hemisphere of the brain is dominant in humans (left-handed in right-handers and right-handed in left-handed people). In general, the frontal lobes are the part of the brain that is responsible for conscious action and decision making. They are a kind of command post.

In right-handers, the right frontal lobe is responsible for monitoring the implementation of non-verbal actions based on the analysis and synthesis of information from receptors and other areas of the brain. She is not involved in the formation of speech, in abstract thinking, prediction of action. The development of a tumor in this part of the brain is threatened by the appearance of psychopathic symptoms. It can be either aggression, or, conversely, apathy, indifference to the world around it, but in any case, the adequacy of a person’s behavior and attitude toward what surrounds him can often be questioned. Such people, as a rule, change their character, negative personal changes appear, control over their behavior is lost, which is noticed by others, but not by the patient.

Localization of a tumor in the region of the precentral gyrus threatens with weakness of muscles of varying degrees, ranging from paresis of the limbs, when movements in them are limited, and ending with paralysis, in which movements are simply impossible. The right-sided tumor causes the described symptoms in the left leg or arm, the left-sided - in the right extremities.

Astrocytoma of the left frontal lobe (in right-handers) in most cases is accompanied by impaired speech, logical thinking and memory of words and actions. In this part of the brain is the motor center of speech (the center of Broca). If the tumor presses on it, it affects the characteristics of pronunciation: the tempo of speech is disturbed, the articulation (it becomes fuzzy, blurred with some “clears” in the form of individual normally pronounced syllables). With a strong defeat of the center of Brock, motor aphasia develops, which is characterized by difficulties in the formation of words and sentences. The patient has the articulation of individual sounds, but can not combine movements to form a speech, sometimes speaks not the words that he wanted to say. [4]  

With the defeat of the frontal lobes violated perception and thinking. Most often, such patients are in a state of gratuitous joy and bliss, called euphoria. Even having learned their diagnosis, they cannot think critically, so they are not aware of the seriousness of the pathology, and sometimes they simply deny its existence. They become initiativeless, avoid situations of choice, refuse to make serious decisions. Often there is a loss of skills formed (by the type of dementia), which causes difficulties in performing familiar operations. New skills are formed with great difficulty.[5], [6]

If an astrocytoma is located at the border of the frontal and parietal regions or is shifted towards the occiput, the usual symptoms are:

• violation of body sensitivity,
• forgetting the characteristics of objects without reinforcement by visual images (a person does not recognize an object by touch and is not oriented in the arrangement of body parts with eyes closed),
• non-perception of complex logical-grammatical constructions related to spatial relations.

In addition to the violation of spatial sensations, patients may complain about the violation of arbitrary (conscious) movements in the opposite hand (the inability to perform even familiar movements, for example, hold the spoon to the mouth).

Left-sided arrangement of parietal astrocytoma is fraught with impaired speech, oral counting, writing. If an astrocytoma is located at the junction of the occipital and parietal parts, reading problems are likely due to the fact that the person does not recognize the letters, this also usually entails violations of the letter (alexia and agraphia). The combined violation of writing, reading and speech occurs when the tumor is located near the temporal part.

Thalamic astrocytoma is a pathology debuting with headaches of a vascular or hypertensive nature and visual impairment. The thalamus is a deep structure of the brain, consisting mainly of gray matter and represented by two visual tubercles (this explains the visual disturbances of a tumor of this localization). This part of the brain mediates the transfer of sensitive and motor information between the large brain, its cortex and peripheral parts (receptors, sensory organs), regulates the level of consciousness, biological rhythms, sleep and wakefulness, and is responsible for concentration.

In the third part of the patients, various sensory impairments are revealed (often superficial, less often deep, occurring on the side opposite to the lesion), half of the patients complain of movement disorders and coordination problems, tremors [7], slow progressing Parkinson's syndrome [8]. In people with astrocytoma of the thalamus (more than 55% of patients), there may be marked in varying degrees pronounced disorders of higher mental activity (memory, attention, thinking, speech, dementia). Speech disorders occur in 20% of cases and are presented in the form of aphasia and temperature-rhythmic disorders, ataxia. The emotional background can also be disturbed, even to violent crying. In 13% of cases, muscle twitching or slowness of movement is noted. Half of the patients showed paresis of one or two hands, and almost all of them had weakened facial muscles of the lower part of the face, which is especially evident in emotional reactions. [9], [10], [11]A case of weight loss in the thalamus astrocytoma has been described [12].

Reduced visual acuity is a symptom associated with an increase in intracranial pressure and detected in more than half of patients with thalamic tumors. With the defeat of the rear parts of this structure is found a narrowing of the visual fields.

When astrocytoma of the temporal region changes the auditory, visual, taste sensations, possible speech disorders, memory loss, problems with the coordination of movements, the development of schizophrenia, psychosis, aggressive behavior [13]. All these symptoms do not have to appear in one person, because the tumor can be located above or below, bordering with other areas of the brain. In addition, the left side or the right side also plays a role.

So astrocytoma of the right temporal lobe is most often accompanied by hallucinations. They can be visual or auditory (visual hallucinations are characteristic of damage to the occipital part, which is responsible for processing and perception of visual information), often combined with a disorder of taste perception (with damage to the anterior and lateral divisions of the temporal lobe). Most often occur on the eve of an epileptic seizure in the form of an aura.[14]

By the way, epiphriscuses with astrocytoma are most likely for tumors of the temporal, frontal and parietal lobes. At the same time, they manifest themselves in every possible variety: convulsions and turns of the head while maintaining or losing consciousness, fading, lack of response to the environment in combination with repetitive lip movements or reproduction of sounds. In milder forms, there is an increase in heartbeat, nausea, disturbances in the sensitivity of the skin in the form of tingling and “ants”, visual hallucinations in the form of a change in the color, size or shape of the object, the appearance of light flashes before your eyes.

With damage to the hippocampus, located on the inner surface of the temporal region, long-term memory suffers. Localization of a tumor on the left (in right-handers) can affect the verbal memory (a person recognizes objects, but cannot remember their names). Both oral and written speech, which a person ceases to understand, suffers. It is clear that the speech of the patient himself is a construction of unrelated words and sound combinations.[15]

The defeat of the right temporal region affects the visual memory, recognition of intonation, previously familiar sounds and melodies, facial expressions. Auditory hallucinations are characteristic of lesions of the upper temporal lobes.

If we talk about persistent symptoms of astrocytoma, which occur regardless of the location of the tumor, then first of all it should be noted headache, which can be both constant aching (this indicates the progressive nature of the tumor), and occur in the form of attacks when changing the position of the body ( characteristic of the early stages).

This symptom can not be called specific, but observations show that it is possible to suspect a brain tumor, if the pain appears already in the morning, and by the evening it subsides. With increased pressure, headache is usually accompanied by nausea, but if intracranial pressure rises (and this can be a growing tumor that squeezes blood vessels and disrupts the flow of fluid from the brain), vomiting may occur, often repeated attacks of hiccups, mental abilities, memory deteriorate, Attention.

Another feature of headaches with astrocytoma of the brain is its widespread nature. The patient can not clearly determine the localization of pain, it seems that the whole headache. As the intracranial pressure increases, the vision deteriorates to complete blindness. The fastest swelling of the brain with all the ensuing consequences occurs during neoplastic processes in the frontal lobes.

Spinal astrocytoma

So far we have been talking about astrocytoma as one of the glial brain tumors. But the nervous tissue is not limited to the cranium, it penetrates the spine through the occipital foramen. The continuation of the initial part of the brain stem (medulla oblongata) is the nerve fiber that extends inside the spinal column to the tailbone itself. It is the spinal cord, which also consists of neurons and glial glue cells.

Spinal cord astrocytes are similar to those in the brain, and they, too, under the influence of some (not fully understood) causes, can begin to divide vigorously, forming a tumor. Astrocytomas of the spinal cord are considered possible causes of the same factors that can provoke tumors from glial cells in the brain.

But if an increase in intracranial pressure and headaches is characteristic of brain tumors, the astrocytoma of the spinal cord may not manifest itself for a long time. The progression of the disease in most cases is slow. The first signs of spinal pain do not always appear, but often (about 80%), and only 15% of patients have a combined appearance of pain in the back and head. With the same frequency, there are also disturbances in the sensitivity of the skin (paresthesias), which are manifested by spontaneous tingling, burning, or running goose bumps and disorders of the pelvic organs due to a violation of their innervation.[16]

Symptoms of motor disorders, diagnosed in the form of paresis and paralysis (weakening of muscle strength or the inability to move the limb), appear already in the later stages, when the tumor becomes large in size and violates the conduction of nerve fibers. Usually the interval between the appearance of back pain and motor disorders is at least 1 month. In later periods, some children also develop spinal deformities.[17]

As for the localization of tumors, most of the astrocytomas are found in the cervical region, less often they are localized in the thoracic and lumbar region.

Spinal cord tumors can occur in younger or older children, as well as in adult patients. However, their prevalence is lower than that of brain tumors (only about 3% of the total number diagnosed by astrocytomas and about 7-8% of the total number of CNS tumors).[18]

In children, spinal cord astrocytomas occur more frequently than other tumors (about 83% of the total), in adults they are in second place after ependymoma (the tumor of their ependymal cells of the ventricular system of the brain - ependymocytes). [19]

Types and degrees

The tumor from astrocytes is one of the many variants of the tumor process in the central nervous system, and the concept of "brain astrocytoma" is very generalized. First, tumors may have different localization, which explains the dissimilarity of the clinical picture with the same pathology. Depending on the location of the tumor, the approach to its treatment may differ.

Secondly, tumors differ morphologically, i.e. Consist of different cells. Astrocytes of white and gray matter have external differences, for example, the length of the shoots, their number and location. Fibrous astrocytes with poorly branching processes are found in the white matter of the brain. Tumors from such cells are called fibrous astrocytomas. For protoplasmic astrogly gray matter, there is a characteristic strong branching with the formation of a large number of glial membranes (the tumor is called a protoplasmic astrocytoma). Some tumors may contain both fibrous and protoplasmic astrocytes (fibrillar protoplasmic astrocytoma).[20]

Thirdly, neoplasms from glial cells behave differently. The histological picture of different variants of astrocytomas shows that among them there are both benign (their minority) and malignant (60% of cases). Some of the tumors go into cancer only in some cases, but you can’t take them to benign tumors anymore.

There are various classifications of astrocytoma brain. Some of them are understandable only to people with medical education. For example, consider a classification based on the difference in the structure of cells, in which there are 2 groups of tumors:

• Group 1 (normal or diffuse tumors), represented by 3 histological types of neoplasms:
  • fibrillar astrocytoma - formation without clear boundaries with slow growth, refers to the diffuse astrocytoma variant, consisting of astrocytes of the white matter of the brain
  • protoplasmic astrocytoma is a rare type of tumor, often affecting the cortex of the cerebral hemispheres; consists of small astrocytes with a small amount of glial fibers, it is characterized by degenerative processes, the formation of a microcist within the tumor[21]
  • hemystocyte or hemystocytic (fat-cell) astrocytoma - poorly differentiable cluster of astrocytes, consists of large angular cells
• Group 2 (special, special, nodal), represented by 3 types:
  • pilocytic (hair-like, hair-like, piloid) astrocytoma is a non-malignant tumor of parallel tufts of fibers, has clearly defined boundaries, is characterized by slow growth, often contain cysts within themselves (cystic astrocytoma) [22]
  • subependymal (granular) giant-cell astrocytoma, subependymoma - a benign tumor, so named because of the gigantic size of its constituent cells and location, often located near the sheaths of the ventricles of the brain, can cause blockage of interventricular holes and hydrocephalus [23]
  • microcystic cerebellar astrocytoma - a nodular formation with small cysts, not prone to degeneration into cancer.

It should be noted that epileptic seizures are more characteristic of the second group of brain astrocytomas.

This classification gives an idea of the structure of the tumor, which is not very clear to the man in the street, but does not answer the burning question of how dangerous different forms of diffuse tumors are. With nodules, everything is clear, they are not prone to degeneration into cancer, but they are much less often diagnosed as diffuse.

Later, scientists made repeated attempts to divide astrocytomas according to their degree of malignancy. The most accessible and convenient classification developed by WHO, taking into account the propensity of different types of astrocytomas to degenerate into a cancer tumor.

In this classification, 4 types of glial tumors from astrocytes are considered, which correspond to 4 degrees of malignancy: 

• 1 group of tumors - astrocytomas of 1 degree of malignancy (grade 1). The structure of this group includes all species of special (benign) astrocytomas: piloid, subependymal, microcystic, pleomorphic xanthoastrocytoma, usually developing in children and young.
• Group 2 tumors - astrocytomas 2 (low) grade (grade 2 or low grade). This includes the conventional (diffuse) astrocytomas discussed above. Such tumors can turn into cancer, but this rarely happens (usually with a genetic predisposition). More common in young people, since the age of detection of fibrillar tumors rarely exceeds 30 years.

Next come a tumor with a high degree of malignancy, which are prone to cell malignancy (high grade).

• Group 3 tumors - astrocytoma grade 3 malignancy (grade 3). Anaplastic astrocytoma is considered to be a prominent representative of this group of tumors - a fast-growing tumor without definable contours, most commonly found in the male population of 30-50 years.
• Group 4 of astrocyte glial tumors is the most malignant, highly aggressive neoplasms (grade 4) with practically fulminant growth, affecting all brain tissue, and necrotic foci are required. A prominent representative is the glioblastoma multiforme (giant cell glioblastoma and gliosarcoma), diagnosed in men over 40 years old and almost incurable due to the almost one hundred percent recurrence tendency. Cases of the disease in women or at a younger age are possible, but occur less frequently. 

Glioblastomas do not have a hereditary predisposition. Their appearance is associated with highly oncogenic viruses (cytomegalovirus, herpes virus type 6, polyomavirus 40), alcohol use and exposure to ionizing radiation, although the influence of the latter has not been proven.

Later in the new versions of the classification, new versions of the already known types of astrocytomas appeared, which nevertheless differ in the probability of degeneration into cancer. So the piloid astrocytoma is considered one of the safest benign varieties of a brain tumor, and its variant pilomixoid astrocytoma is a rather aggressive tumor with rapid growth, a tendency to relapse and the possibility of metastasis.[24]

The pilomixoid tumor has some similarity with the piloidal location (most often it is the area of the hypothalamus and optic chiasm) and the structure of the cells that constitute it, but it also has many differences, which allowed it to be separated into a separate form. Diagnose the disease in young children (average age of patients 10-11 months). Tumors assigned grade 2 malignancy.