Brain Tumors: Types, Symptoms, Diagnosis, and Treatment Methods

Brain Tumors, Their Types, Symptoms, Diagnosis, and Treatment Methods

In this article on Brain Tumors, Their Types, Symptoms, Diagnosis, and Treatment Methods, we cover the following topics: Superficial Metastatic Brain Tumors, Deep Metastatic Brain Tumors, Skull Base Tumors, Posterior Fossa Tumor Surgery, Cerebellopontine Angle Tumor Surgery, Simple Tumoral Masses of the Skull Bone/Scalp, Intraventricular Tumors of the 3rd Ventricle, Intraventricular Tumors of the 4th Ventricle, Convexity Tumor Surgery, and Cervical Intramedullary Tumor Excision.

Superficial Metastatic Brain Tumors

Metastatic brain tumors are tumors that form in the brain as a result of cancer spreading from another part of the body. In superficial metastatic brain tumors, the tumor is located on the outer surface of the brain. Metastatic brain tumors are the most common type among all brain tumor types. According to autopsy studies, metastatic brain tumors—which occur more frequently than all other brain tumor types combined—are found in 20-50% of cancer patients.

The cancer types most commonly responsible for causing metastatic brain tumors are breast cancer in women and lung cancer in men. Metastatic brain tumors generally occur when cancerous cells from another region of the body reach the brain through the bloodstream. Cancerous cells that enter the bloodstream travel to the brain and cause the formation of new cancerous cells in that region. For this reason, metastatic brain tumors most often develop in areas of the brain with richer blood circulation.

Metastatic brain tumors most frequently occur in multiple numbers. Accordingly, the treatment approach for metastatic brain tumors is planned based on the number, size, and location of the metastases. Since metastatic brain tumors fundamentally consist of cancerous cells that grow and multiply abnormally, the space they occupy within the brain leads to an increase in intracranial pressure.

For this reason, the symptoms of metastatic brain tumors are similar to those of increased intracranial pressure. These symptoms may include nausea, vomiting, visual disturbances, loss of strength in different parts of the body depending on the affected brain region, tingling, loss of sensation, and in some cases, seizures. When such symptoms appear in a cancer patient in particular, prompt medical consultation and necessary examinations should be sought without delay.

Once metastatic brain tumors have been identified, the treatment process may involve chemotherapy, radiotherapy, surgery, or a combination of these treatment methods, depending on the patient's condition. If metastatic brain tumors are not treated promptly, they pose very serious life-threatening risks. Radiotherapy is the most commonly used treatment method.

In radiotherapy, the growth and multiplication of tumor cells are halted through radiation, and these cells are destroyed, resulting in tumor shrinkage. The effectiveness of radiotherapy varies depending on the type of cancerous cell. Some cancer cells are significantly affected by the radiation applied and are easily brought under control, while other types of cancerous cells do not respond sufficiently to radiotherapy. In such cases, surgical options may need to be applied in addition to radiotherapy.

Metastatic brain tumor surgery is most commonly performed on tumors that are not scattered, are located in a specific region, are large, and cause neurological symptoms. The superficial location of a metastatic brain tumor facilitates its identification prior to surgery and access to it during the procedure, allowing for less damage to brain tissue and thereby reducing the side effects and risks of surgery.

Following metastatic brain tumor surgery, radiotherapy or chemotherapy may be administered to support the treatment. Although chemotherapy is not as effective as surgery or radiotherapy in treating metastatic brain tumors, it can contribute to extending survival in certain types of cancerous cells.

Deep Metastatic Brain Tumors

In deep metastatic brain tumors, the tumor is located within the deep tissue of the brain. In cases of metastatic brain tumors found in the brain's deep tissues, complex functions such as the patient's mood regulation, memory, and learning abilities may be affected depending on the location of the tumor. The deep location of a metastatic brain tumor complicates its identification prior to surgery and access to it during the procedure, thereby increasing the side effects and risks of surgery.

Skull Base Tumors

The skull base is a complex anatomical bone structure formed by the frontal, ethmoid, sphenoid, temporal, and occipital bones, serving as a barrier between the brain and neck tissues. Since clinical evaluation of skull base tumors is limited, computed tomography (CT) and magnetic resonance imaging (MRI) methods play an extremely important role in the diagnosis and treatment process of these patients.

Particularly in recent years, advances in imaging methods have made it possible to clearly determine tumor boundaries prior to surgery and to reveal the relationships of tumors with vital neural and vascular structures. This has enabled surgeons to develop approaches that minimize vital risks as much as possible while achieving the best possible tumor clearance.

Detailed knowledge of skull base anatomy is essential for accurately evaluating the location, extension, and relationships of skull base tumors with surrounding critical tissues, as well as for determining tumor characteristics. The skull base consists of different bones named the frontal, ethmoid, sphenoid, temporal, and occipital bones.

The skull base, with its numerous different foramina and grooves formed by these bones, constitutes a quite intricate anatomical structure and serves almost as a barrier between intracranial tissues and extracranial soft tissues. It is also the most important structure protecting vital intracranial structures from external factors. Both benign and malignant bone tumors, as well as metastases, can be seen in the skull base. Metastatic tumors are among the most common tumor types seen in the skull base in adult patients.

Since metastatic tumors frequently spread via the bloodstream, they most commonly arise in skull base structures with dense bone marrow, such as the clivus, petrous apex, sphenoid triangle, and the diploic cavity of the calvarium. Aside from this, the most common malignant tumor of the skull base is osteosarcoma, which is generally seen in individuals who have previously received radiotherapy and in patients with Paget's disease.

Osteosarcomas are characterized by bone formation and the aggressive periosteal reaction that accompanies this formation process. Apart from these, skull base tumors can occur in many different regions and forms. Depending on the region in which they arise, as well as the tumor's type, extension, and size, they may cause various symptoms and, in advanced cases, may pose vital risks and cause permanent damage to the patient.

Depending on the tumor's location, anatomical structures such as the frontal fossa, temporal fossa, sphenoid bone, and clivus may be affected. Frontal fossa tumors are those affecting the anterior region of the skull base. Temporal fossa tumors arise on the lateral sides of the skull base. The sphenoid bone, another region where skull base tumors may occur, is a bone located in the central part of the skull base that also contributes to the formation of the anterior portion of the temples.

The clivus, another structure, forms part of the skull base and is responsible for protecting the brain and separating it from other structures around the face and neck. Skull base tumors can thus arise in many different regions in this manner. Depending on their location, they may cause various effects both in the brain and in surrounding tissues. Accordingly, skull base tumors may present with many different symptoms in affected patients and, if left uncontrolled, may in some cases pose serious vital risks.

Posterior Fossa Tumor Surgery

The posterior fossa is the name given to the anatomical structure corresponding to the posterior one-third of the skull. The regions in which brain tumors arise can vary according to age. Posterior fossa tumors may be located in either the supratentorial or infratentorial region. In adult patients, approximately 70-75% of brain tumors occur in the region called the supratentorial region, located between the cerebellum and the brain but close to the brain.

In childhood, however, the rate of tumors located in the region called the infratentorial region—situated between the cerebellum and the brain but close to the brain—is at the level of 60-70%. The symptoms and signs of posterior fossa tumors initially develop due to increased intracranial pressure, and secondarily due to pressure on neurological structures called the cerebellar nuclei and the brainstem.

They may also cause blockage in the circulation pathways of the cerebrospinal fluid (CSF) found throughout the brain and spinal cord in our body, leading to a health problem called hydrocephalus, in which cerebrospinal fluid accumulates and causes increased intracranial pressure; patients may present to the doctor with signs and symptoms related to hydrocephalus.

In patients with posterior fossa tumors, different findings may be observed depending on the tumor's location, type, size, and the patient's general condition. However, patients generally present to the doctor with findings such as headache, nausea, vomiting, dizziness, imbalance, ataxia (a coordination disorder affecting movements), diplopia (a type of visual disturbance causing double vision), loss of strength, and visual impairment. Due to the structure of the posterior fossa, the time between the onset of patient complaints and the diagnosis of a posterior fossa tumor is quite short compared to other brain tumors.

Depending on the severity of the tumor, this period may be even shorter, dropping to as little as 1 week. However, in some benign tumors, this period may extend up to 1 year. Once the diagnosis of a posterior fossa tumor is confirmed, a decision is made regarding which treatment method will be used. When surgical treatment is decided upon, the tumor must be identified in particular detail prior to posterior fossa tumor surgery, the surrounding tissues must be thoroughly understood, and advanced imaging methods must be utilized in developing the surgical procedure.

After the surgical procedure is determined by the surgeon, surgery for posterior fossa tumors is mostly performed in a sitting position with the assistance of a pin-fixed headframe. However, this may vary depending on the patient's general condition and the surgeon's judgment. Depending on the tumor's location, access may be made from different regions to remove the tumor. Likewise, depending on the tumor's location and structure, either all or part of it may be removed.

In cases where the tumor is malignant or cannot be completely removed, treatment methods such as chemotherapy and radiotherapy are used in addition to surgical treatment. The treatment of posterior fossa tumors has made great progress in recent years thanks to advances in diagnostic and treatment methods, improvements in surgical techniques and surgical technologies, advances in supportive care, and support from treatments such as chemotherapy and radiotherapy, enabling promising outcomes to be achieved for patients through treatment.

Cerebellopontine Angle Tumor Surgery

In medical terminology, the junction between the cerebellum and the brainstem is referred to as the cerebellopontine angle. Many different types of tumors can develop in this region. However, the most common tumor type—and the one that comes to mind first when referring to cerebellopontine angle tumors—arises from the sheath of the eighth cranial nerve, the vestibular nerve, which is responsible for balance and hearing. These tumors are generally benign and slow-growing in nature.

Cerebellopontine angle tumors most commonly cause hearing and balance problems, as they typically compress the vestibular nerve. If a cerebellopontine angle tumor grows significantly, it may extend toward the face and compress the nerve responsible for facial sensation. In such cases, facial numbness may occur. Tumors that continue to grow larger can cause severe compression, leading to serious damage to these nerves, with findings potentially progressing to facial paralysis.

Similarly, an excessively enlarged cerebellopontine angle tumor can compress the brainstem, creating a life-threatening situation and causing serious, permanent damage to the patient. Cerebellopontine angle tumors are most often unilateral. However, in the presence of a condition known as neurofibromatosis type 2, these tumors may occur bilaterally.

Among all brain tumors, cerebellopontine angle tumors account for approximately 8%. Early diagnosis is crucial in preventing the tumor from growing to a size that could cause permanent damage or life-threatening findings. In most patients with cerebellopontine angle tumors, the first symptom to appear is hearing loss. Due to involvement of the vestibular nerve, symptoms such as dizziness, headache, and tinnitus may also occur. In cerebellopontine angle tumors that have reached significant size, facial paralysis, double vision, swallowing difficulties, facial pain, and numbness may be observed.

For this reason, consulting a physician while symptoms are still in the early stages is important for controlling the disease early on. When planning surgical treatment for cerebellopontine angle tumors, the surgical procedure is determined based on the tumor type, its relationship with other nerves, and the condition of the surrounding tissues. In small tumors detected through early diagnosis, surgical treatment is easier to perform, and the risk of undesired postoperative side effects, such as hearing loss, is significantly lower.

However, surgery for larger tumors is more challenging, and the nerves and surrounding tissues in the region may have already sustained permanent damage due to the intense pressure created by the tumor. In such cases, even if the tumor is completely removed through surgery, the damage it has left behind may be permanent. Surgical treatment yields quite favorable outcomes for cerebellopontine angle tumors, and the recurrence risk following surgery is less than 5%. Beyond the damage the tumor itself may cause, the surgical treatment itself may also carry certain complications.

These complications include cerebrospinal fluid leakage, meningitis (inflammation of the meninges, the membrane surrounding the brain and spinal cord), hydrocephalus (excess accumulation of cerebrospinal fluid), and wound infection. In addition, another complication encountered more frequently, particularly during surgery for large cerebellopontine angle tumors, is facial paralysis.

The risk of facial paralysis in cerebellopontine angle tumor surgeries has been reported to range between 5% and 30%. Even after the cerebellopontine angle tumor has been successfully removed through surgery without permanent damage, balance problems and headaches may continue for an extended period afterward. Today, thanks to advancing surgical techniques and technologies, cerebellopontine angle tumors can be treated far more effectively and with significantly fewer complications.

Intraventricular Brain Tumors (3rd Ventricle)

The ventricles are fluid-filled cavities within the brain containing cerebrospinal fluid. There are four ventricles in the human brain. Brain tumors can develop within these ventricles. The incidence of intraventricular tumors ranges from 12% to 20% among all types of intracranial tumors.

Of intraventricular tumors, 15% are located in the 3rd ventricle. Due to the location of intraventricular tumors and their tendency to grow slowly over time, the onset of symptoms in patients with intraventricular tumors may be delayed. Additionally, because symptoms appear late, diagnosis may be delayed, and large-sized tumors may be encountered by the time of detection.

In intraventricular tumors, preoperative evaluation, patient-specific planning, patient management, and the type of surgical treatment are important considerations. Key factors that must be determined include the tumor's location, size, cellular structure, its spread within the ventricle, its main blood supply, the functional brain areas it affects, and the degree of neurological impairment present in the patient.

The goal of intraventricular tumor surgery is to reach and remove the tumor via the approach that best preserves the brain's critical blood vessels and tissue. Depending on the tumor's size, shape, and location, symptoms associated with increased intracranial pressure may occur, including headache, visual disturbances, difficulty speaking, confusion, irritability, forceful vomiting, high fever, sensory loss and tingling sensations, neck stiffness, and seizures.

In addition, depending on the tumor's characteristics, patients may also experience movement disorders, paralysis of certain nerves, partial or complete vision disturbances, and hormonal imbalances. The detection of intraventricular tumors relies on these symptoms, clinical tests, and imaging methods.

With the help of computed tomography and magnetic resonance spectroscopy, the location of an intraventricular tumor can be determined, allowing treatment to be planned accordingly. Once the tumor's location and characteristics have been identified, surgical planning becomes a challenging and critically important procedure. During this planning process, when determining the surgical pathway to reach the intraventricular tumor, the surgeon must take into account the characteristics of the brain tissues at risk, the importance of these tissues to overall bodily function, and the potential complications that may arise following surgical treatment.

Intraventricular tumor surgeries are demanding procedures, both in terms of planning and execution. It is essential that the surgeon possesses a high level of mastery over all structures related to the ventricle. Based on the surgical plan developed, the surgeon determines the intracranial pathway to be used to reach the intraventricular tumor and the point of entry into the skull.

Depending on the specific characteristics of the surgery and the pathway chosen, the risk of complications arising during or after surgery may vary. Ultimately, the goal of such surgeries is to remove the intraventricular tumor as effectively as possible while causing the patient the least amount of harm. Following surgical intervention, as the tumor's effect on the affected region subsides and intracranial pressure decreases, improvement in symptoms—and even complete recovery without any lasting functional impairment—may be observed.

Intraventricular Tumors (4th Ventricle)

Of intraventricular tumors, 5% are located in the 4th ventricle. In 4th ventricle intraventricular tumors, depending on the tumor's size, shape, and location, symptoms associated with increased intracranial pressure may occur, including headache, visual disturbances, difficulty speaking, confusion, irritability, forceful vomiting, high fever, sensory loss and tingling sensations, neck stiffness, and seizures. Given that critical structures surrounding the 4th ventricle can lead to serious, permanent health problems if damaged, it is essential that the surgeon possesses a high level of mastery over all structures related to the ventricle.

Simple Tumoral Masses of the Skull Bone / Scalp

Since the clinical evaluation of skull tumors is limited, computed tomography (CT) and magnetic resonance imaging (MRI) play a highly important role in the diagnosis and treatment process of these types of patients. Detailed knowledge of skull anatomy is essential for accurately assessing the location, extension, and relationship of skull tumors with the surrounding important structures, as well as for determining the characteristics of the tumors.

The skull is composed of different bones named the frontal, ethmoid, sphenoid, temporal, and occipital bones. The skull is a highly complex anatomical structure due to the numerous different foramina and grooves formed by these bones, and it essentially serves as a barrier between intracranial structures and extracranial soft tissues. Both benign and malignant bone tumors, as well as metastases, can be observed in the skull. Metastatic tumors are among the most common tumor types seen in the skull in adult patients.

Since metastatic tumors typically spread through the bloodstream, they most commonly occur in skull structures with a dense concentration of bone marrow, such as the clivus, petrous apex, sphenoid trigone, and the diploic cavity of the calvarium. Aside from this, the most common malignant tumor observed in the skull is osteosarcoma, which is generally seen in individuals who have previously received radiotherapy and in patients with Paget's disease. Apart from these, skull tumors can also be observed in many different regions and forms.

Aside from the skull bone, various tumoral formations can also be observed on the scalp. Approximately 2% of skin tumors occur on the scalp. These tumors may arise directly on the scalp or as metastases transmitted from another region of the body. The presence of hair on the skin often makes tumor detection more difficult and delays diagnosis.

This situation can allow a tumor arising on the scalp to progress significantly before it is detected, making treatment of the condition more difficult. While 1-2% of all scalp tumors are malignant, scalp tumors constitute 13% of all malignant skin tumors. Risk factors for malignant scalp tumors can be listed as ultraviolet exposure, radiotherapy, and genetic predisposition.

Some studies indicate that men with short hair are at greater risk due to increased ultraviolet exposure, while women are at lower risk thanks to the protection their hair provides against ultraviolet rays. For this reason, precautions such as avoiding prolonged sun exposure during times when sunlight intensity may be harmful, and wearing a hat when necessary, are important for protection against scalp tumor risks.

Convexity Tumor Surgery

Convexity tumors are observed as convexity meningiomas. Meningiomas are slow-growing, mostly benign tumors that develop in the membranes surrounding the brain. For this reason, the symptoms that arise may progress in a mild manner.

Today, advances in imaging techniques such as computed tomography and magnetic resonance imaging, along with more frequent radiological examinations, have increased the incidental detection rate of these types of tumors. Since meningiomas arise not within the brain itself but in the brain membrane, they are technically not classified as brain tumors.

However, meningiomas cause brain-related symptoms due to the pressure they exert on the brain. Patients with meningiomas most commonly seek medical attention due to slowly progressing headaches. In many cases, however, meningiomas can remain silent throughout a person's lifetime without causing any symptoms. In such cases, these meningiomas are only detected during check-ups or examinations conducted for other reasons.

Although convexity meningiomas generally occur in the upper and outer regions of the brain, they can cause different symptoms in patients depending on the specific area in which they arise. These symptoms can be listed as headache, seizures, weakness in the arms and legs, vision and hearing loss, difficulty in clear thinking, walking problems, and loss of smell. However, if left uncontrolled, tumors that grow excessively can exert intense pressure on the brain and even the spinal cord, leading to very serious life-threatening problems.

These problems can be listed as headaches unresponsive to painkillers, paralysis, hormonal disorders, vision loss, epileptic seizures, and brain hemorrhages. The exact causes of meningioma formation are not known with certainty. However, studies suggest that factors such as genetic factors, radiation exposure, head trauma, and hormonal changes may play a role in the development of meningiomas.

Since meningiomas generally do not metastasize, progress slowly, and are benign, their treatment and monitoring can be carried out easily when detected early. However, this slow progression and the gradual emergence of symptoms can sometimes make diagnosis difficult and allow the tumor to progress further. For this reason, imaging methods and neurological examinations are very important for early diagnosis.

After a diagnosis of a convexity tumor is made, surgical treatment is usually the first treatment option. However, depending on the shape, size, location, and extension of the convexity tumor, complete removal of the tumor may sometimes not be possible, or surgical intervention may carry high life-threatening risks. In addition, clinical follow-up may be preferred over surgical treatment for small, incidentally detected convexity tumors that do not cause symptoms.

If it is determined during follow-up that the convexity tumor is not growing, or even if it grows, it has not reached a size that could harm the patient, and that it is of a type that shrinks during menopause, the patient may continue their life without treatment. However, if it is determined during follow-up that the tumor is growing and causing symptoms in the patient, surgical treatment is applied. Meningioma surgery is largely successful, and significant improvement in the patient's symptoms is observed following surgical treatment.

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Cervical Intramedullary Tumor Excision

Spinal cord tumors are tumors that develop on or within the spinal cord. They are generally described as benign, slow-growing tumors. Approximately one-fifth of central nervous system tumors are located within the spinal canal. Spinal cord tumors are classified according to their location as extradural, intradural extramedullary, and intramedullary (within the spinal cord itself).

Extradural tumors are located outside the dura mater, the membrane surrounding the spinal cord. Intradural extramedullary tumors are located within the dura mater but outside the spinal cord. Intramedullary tumors are located within both the dura mater and the spinal cord itself. The majority of intradural extramedullary tumors consist of schwannomas, neurofibromas, and meningiomas, while a smaller portion consists of dermoid, epidermoid, angioma, lipoma, and ependymoma-type tumors. Intramedullary tumors, on the other hand, are generally of the ependymoma and astrocytoma types.

In addition, intramedullary tumors of the hemangioblastoma, dermoid, epidermoid, lipoma, teratoma, and oligodendroglioma types may also occur. Ependymoma-type tumors are the most common in adults and typically affect the lumbosacral region. Astrocytoma-type tumors are more common in children and young adults, generally occurring in the thoracic and cervical regions. Spinal cord tumors may present with varying findings depending on their location and the nerve and spinal cord segments they affect. Pain is the most common symptom in most spinal cord tumors. Pain may occur in different regions of the spine, its location may vary, and it may intensify with physical activity. When the tumor compresses the spinal cord, signs of spinal cord compression emerge.

Compression occurring in the cervical region presents with symptoms such as numbness, pain, and tingling in the neck and arms. Spinal cord tumors progress over time with worsening weakness, sensory loss extending to the arms and legs, pain, and numbness. Depending on the structure and growth rate of the tumor, symptoms may worsen slowly or rapidly. Spinal cord tumors can be diagnosed using computed tomography, magnetic resonance imaging, scintigraphy, or positron emission tomography methods. A biopsy may be performed to examine the structure and type of the tumor. Various surgical treatment methods are applied in the treatment of spinal cord tumors.

The aim of surgical treatment is to achieve complete or partial removal of the tumor and to eliminate the pressure caused by it. The surgical treatment approach is determined by evaluating characteristics such as whether the tumor is benign or malignant and its structural features. In cervical intramedullary tumor excision, the region of the spinal cord where the tumor is located is incised and the tumor is removed. Benign tumors of intradural and intramedullary location that are not excessively large can be removed relatively easily. Cervical intramedullary tumor excision surgery may, when necessary, be performed together with laminectomy or laminotomy techniques.

When clearing the spinal cord alone is not sufficient, adjacent vertebral segments may also be removed. If the tumor is not completely removed after surgery, there is a possibility of tumor regrowth. In such cases, additional treatments such as chemotherapy and radiotherapy are applied to prevent the tumor from growing back. Hygiene of the surgical site is of great importance following cervical intramedullary tumor excision.

Regular dressing changes, avoidance of strenuous physical activity, and uninterrupted adherence to medication therapy help accelerate recovery. Following a successful cervical intramedullary tumor excision, the patient's signs of spinal cord compression resolve. The recovery period varies depending on the size of the tumor.