What are the other Names for this Condition? (Also known as/Synonyms)

• Endothelial Meningioma
• Meningothelial Meningeal Tumor
• Syncytial Meningioma

What is Meningothelial Meningioma? (Definition/Background Information)

• Meningioma is a mostly benign tumor that arises from the meninges which is the membranous tissue encasing the central nervous system (brain and spinal cord). The meninges consist of three layers, namely the outer layer (dura mater), the middle layer (arachnoid mater), and the inner layer (pia mater); together, they form the protective lining around the brain
• Meningiomas are rare and usually slow-growing tumors that are typically diagnosed in older individuals (60 years and above). The World Health Organization (WHO) classifies meningiomas based on their behavior as benign (grade I), atypical (grade II), and malignant (grade III) tumors. The grade and histologic subtype of the tumor is determined by the pathologist after examining a tissue biopsy of the tumor, under a microscope
• Meningothelial Meningioma is the most common subtype of benign meningioma that generally originates from the parasagittal region or sphenoid ridge of the brain, or from the spinal region. According to WHO classification, Meningothelial Meningiomas are grade I brain tumors, meaning they are the most benign of the brain tumors
• WHO grade I benign tumors are low-grade tumors that are slow-growing and not known to infiltrate into the surrounding tissues. These tumors also offer a very high chance for surgery to be curative, thus having the best prognosis amongst all brain tumors; long-term survivals are usually noted
• The cause of Meningothelial Meningioma is not well understood, but certain genetic abnormalities have been implicated. In general, the risk factors for meningioma may include ionized radiation exposure, hormonal factors in women, breast cancer history, and a family history of meningiomas
• The signs and symptoms depend on the size and location of the tumor and may include headaches, weakness in arms or legs, and vision and speech problems. Complications associated with the tumor include memory loss, personality changes, and seizures. Normally, there is a delay in diagnosing slow-growing and asymptomatic tumors, which may result in additional complications
• Once diagnosed, the treatments for Meningothelial Meningioma may include a combination of surgery, radiation therapy, and the administration of certain drugs to slow progression of the tumor, based on the healthcare provider’s assessment. The prognosis for individuals is generally good in a majority of cases, since the tumor is benign (WHO grade I tumor)

Who gets Meningothelial Meningioma? (Age and Sex Distribution)

• Meningothelial Meningioma is the most common histological subtype of meningioma, and it constitutes between 58-63% of all meningiomas
• Meningiomas are common in individuals over 60-65 years of age; these tumors are rarely noted in children below the age of 14 years
• Both males and females are affected; although, a female predominance is noted, especially in the 21-50 years’ age group
• Worldwide, individuals of all racial and ethnic groups may be affected. People of African origin have a higher risk for meningiomas than people of American or European descent (Caucasians)

What are the Risk Factors for Meningothelial Meningioma? (Predisposing Factors)

Meningothelial Meningioma is the most common subtype of meningioma and the predisposing factors for meningioma, in general, include:

• Increasing age, since most tumors are detected in elderly adults
• Individuals who have been exposed to both low-dose and high-dose ionizing radiation have presented an increased incidence of these tumors
  • Dental X-rays are the most common situation of an individual being exposed to low-dose radiations
  • Studies have shown an increased incidence of meningiomas in individuals who have received multiple full oral dental X-ray examinations
• Individuals, who have undergone radiation therapy for squamous cell carcinoma of the head and neck region, are at an increased risk
• A positive family history of these meningeal tumors could place one at an elevated risk
• Hormonal factors: Studies have shown a correlation between hormones and meningiomas. An increased incidence of these tumors is noted in post-pubertal females compared to males. Histopathology studies have detected the presence of hormonal receptors for estrogen, progesterone, and testosterone, in a vast majority of meningiomas
• Breast cancer history: There is an increased incidence of meningioma in women diagnosed with breast cancer, since hormonal influence play an important role in the development of breast cancer. Therefore, hormones are believed to play a contributory role in the development of meningiomas
• Neurofibromatosis type 2 (NF2): It is a multisystem genetic disorder affecting the nervous system, skin, and skeletal muscles. Individuals with NF2 are known to develop meningiomas in 50-75% of the cases
• Obesity: Having excess body fat may increase one’s risk for meningioma; although, there is presently no conclusive evidence to link the two
• Inhalation of cigarette/tobacco smoke and excess consumption of nitrites in food are other potential risk factors that have been put forth by medical research

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Meningothelial Meningioma? (Etiology)

The exact cause of formation of Meningothelial Meningioma development is unknown. It is researched that certain genetic, environmental, and occupational factors may contribute towards the development of these tumors.

Studies have shown certain molecular mutations in Meningothelial Meningioma.

• Involvement of AKT1E17K and SFRP1 genes that are commonly noted
• These tumors are not known to show mutations on the NF2 gene
• In many cases, features of fibrous meningioma may be noted admixed with the tumor (in about 40% of the cases)

Overall, the following factors have been identified as playing a role in meningioma development:

• Abnormalities on the 22nd chromosome (loss of chromosome 22) in areas that confer suppression of tumor growth; this is reportedly noted in most meningiomas
• 25% of the tumors reportedly exhibit mutations involving the TRAF7 gene
• Some meningiomas have extra platelet-derived growth factor receptors (PDGFR) and epidermal growth factor receptors (EGFR) that can contribute to tumor growth. These receptors are essential for normal cell growth and development

It is possible that female hormones, exposure to ionizing radiation, or an inherited disorder of the nervous system, may cause abnormal cell divisions in the meninges. Studies to characterize these processes are currently underway.

Several studies have documented an altered rate of growth of meningioma in relation to menstrual cycles and pregnancy phases. A clear association between oral contraceptives and hormonal replacement therapy has not been yet established. Research is ongoing to study this association.

In general, it is known that tumors form when normal, healthy cells begin transforming into abnormal cells - these cancer cells grow and divide uncontrollably (and lose their ability to die), resulting in the formation of a mass or a tumor.

What are the Signs and Symptoms of Meningothelial Meningioma?

The signs and symptoms of Meningothelial Meningiomas may differ from one individual to another. It may be mild or severe, depending on several factors. The onset of symptoms and speed of progression of the tumor can vary. In many individuals, tumors that grow slowly and remain asymptomatic, are only diagnosed during certain radiological imaging studies of the head and neck region, which are performed for unrelated health conditions.

Typically, the signs and symptoms of meningioma depend on the location of the tumor, grade of the tumor, and size of the tumor. The tumors may grow to significant sizes before exhibiting any symptoms, which can vary depending on the region of the brain or spinal cord involved.

According to some studies, Meningothelial Meningiomas are known to arise from the following locations in the central nervous system:

• Parasagittal region, in 24% of the cases
• Sphenoid ridge, in 20% of the cases
• Cerebral convexity (on the brain outer curved surface), in 16% of the cases
• Anterior parafalcine region (meningeal layer between brain hemispheres), in 16% of the cases
• Olfactory groove, in 8% of the cases
• Spinal cord involvement is also commonly noted

Some signs and symptoms of the tumors include:

• Headaches; some individuals may have severe headaches, especially in the mornings or with physical activities
• Convulsions (seizures) that may be of any type such as:
  • Myoclonic seizures
  • Grand mal (tonic-clonic) seizures
  • Sensory seizures
  • Complex partial seizures
• Personality changes
• Nausea and vomiting
• Blurred vision
• Visual and hearing impairment
• Muscle weakness; weakness in arms or legs
• Speech problems
• Memory loss
• Some tumors grow rapidly during pregnancy

Large tumors can cause significant signs and symptoms. Most of the tumors are single, but occasionally multiple tumors can be detected growing simultaneously (particularly in individuals with neurofibromatosis type 2), either in the brain region or in association with the spinal cord. The associated symptoms of the underlying condition, if any present, may be noted.

Some of the signs and symptoms based upon tumor location include:

• Involvement of the spinal cord may lead to back pain, chest pain, and/or pain in the arms and legs, depending on the nerves that are compressed by the tumor; severe cases may result in loss of bowel and bladder control
• Tumors at the sphenoid regions can cause vision impairment, double vision, bulging of eyes, increased eye pressure, and numbness of the face 
• Tumors in the olfactory groove mainly affect one’s sense of smell
• The functioning of brain may be severely compromised when the tumors are located at the falx and parasagittal region and cerebral convexity. It can also result in convulsions, weakness in the lower limbs, unsteady gait, coordination issues, and swallowing difficulties

How is Meningothelial Meningioma Diagnosed?

A vast majority of meningiomas may remain undiagnosed because they are asymptomatic. Often, the slow appearance of symptoms (into old age) may result in the healthcare provider attributing the origin of such symptoms as part of a normal aging process. The slow development of symptoms, or the presence of mild symptoms, may also contribute to a delayed detection and diagnosis of these tumors. The tumors may be detected when there is a sudden worsening of symptoms prompting the healthcare provider to perform radiological studies of the brain and/or spinal cord.

A diagnosis of Meningothelial Meningioma may include the following tests and exams:

• Complete physical examination with thorough evaluation of the individual’s medical history (including family history of NF2)
• Assessment of the presenting signs and symptoms
• Visual field tests; tests to assess visual acuity
• Neurological, motor skills, and cognitive assessment:
  • Checking intellectual ability, memory, mental health and function, language skills, judgment and reasoning, coordination and balance, reflexes, sensory perceptions (space, sight, hearing, touch)
  • The healthcare provider/neurologist may use the Karnofsky Performance Scale in order to assess the neurological functioning of the individual’s central nervous system (CNS)
• Electromyography with nerve conductivity tests
• Imaging tests including:
  • X-ray of head and neck; X-ray of the spine
  • Computerized tomography scan (CT scan) of head and neck region and vertebral column; CT with contrast
  • Magnetic resonance imaging scan (MRI scan) of the brain and spinal cord; with contrast agents such as gadolinium
  • Cerebral angiographic studies or magnetic resonance angiography: An angiogram involves injecting dye into the bloodstream, which makes the blood vessels to appear visually on X-rays. The X-ray may show a tumor in the brain or the blood vessels leading into the tumor
  • Magnetic resonance spectroscopy: This radiological technique is used to study the chemical profile of the tumor. It is often performed with and compared to corresponding MRI scan images of the affected region
  • Positron emission tomography (PET scan): A PET scan is a nuclear medicine imaging technique that uses three-dimensional images to show how tissue and organs are functioning. It may be performed to detect any malignancy, and if there is a metastasis (spread) of the tumor to other regions
• Cerebrospinal fluid analysis, where a spinal tap or lumbar puncture procedure may be performed: This diagnostic test is used to remove a sample of cerebrospinal fluid (CSF) from the spaces in and around the brain and spinal cord. The sample is removed from the lower spinal cord using a thin needle, and it is then checked for the presence of cancer cells

Tissue biopsy: A biopsy of the affected region (brain) is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy sample under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy sample under a microscope by a pathologist is helpful in arriving at a conclusive diagnosis. 

There are two ways to perform a biopsy:

• First, a biopsy can be performed as part of a surgical procedure to remove the brain tumor
• Second, a stereotactic needle biopsy can be performed when the tumor is deep within the brain or located in a sensitive area. In this procedure, the surgeon drills a small hole (called a burr hole) into the skull. A thin needle, guided by CT or MRI scanning, is then inserted through the hole to help in the removal of tissue

A differential diagnosis (both radiological and pathological) to eliminate other conditions or tumor types may be considered, before arriving at a definitive diagnosis. These may include:

• Hemangiopericytoma
• Langerhans cell histiocytosis
• Metastatic tumors to the brain and/or spinal cord
• Rosai-Dorfman disease (RDD)
• Solitary fibrous tumor (SFT)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Meningothelial Meningioma?

The possible complications associated with Meningothelial Meningioma include:

• Emotional and mental stress for both the patients and the caretakers, due to the diagnosis and treatment of a brain tumor
• Large undetected tumors can severely affect brain function and be disabling or even life-threatening, due to mass effect/compression of brain tissue
• Large tumors may also press against the skull (or other) bones causing it to expand
• Trouble with concentration
• Severe loss of memory
• Dementia including personality changes causing a reduced quality of life
• Peritumoral brain edema (PTBE): Presence of fluid around the tumor region in the brain resulting in severe symptoms and complications

Complications may arise from surgery, radiation therapy, or other treatment modalities. These may lead to long-term side effects, particularly in children and older adults.

Surgical complications:

• Damage to the muscles, vital nerves, and blood vessels, during surgery to remove the tumor; injury to unaffected brain tissue during surgery
• Post-surgical infection at the wound site is a potential complication
• Sometimes, removing the tumor can worsen the signs and symptoms in some individuals
• Infrequently, recurrence of the tumor after surgery is observed, due to incomplete tumor removal

Chemotherapy side effects depend on the type of chemotherapy medication used and may include:

• Nausea and vomiting
• Hair loss
• Mouth sores
• Loss of appetite
• Diarrhea
• Fatigue
• Increased risk for infections
• Easy bruising
• Infertility

Radiation therapy can cause short-term side effects. It depends on the type used and may include:

• Nausea and vomiting
• Hair loss
• Dryness of mouth; loss of taste
• Headaches
• Fatigue
• Skin color changes; usually darkening of skin on the face and neck may be noted
• Speech and hearing difficulties
• Memory issues
• Seizures

Long-term side effects (seen after 6 months or beyond) may include loss of memory, impaired brain function, and appearance of symptoms that mimic stroke.

How is Meningothelial Meningioma Treated?

The treatment modality for meningioma is chosen, depending on the size, type (whether the tumor is benign, atypical, or malignant), location, and stage of the tumor, tumor growth rate, age and health status of the individual. Tumors that are small and slow-growing usually may be observed and no treatment necessitated, based on the healthcare provider’s assessment. Often, a multidisciplinary team of specialists including neurologists, oncologists, surgeons, radiation therapy experts, and other healthcare professionals are involved in managing the condition.

The treatment measures for Meningothelial Meningioma may include:

• Wait and watch approach by the healthcare provider:
  • Observation of the tumors is often recommended in individuals with small-sized tumors, slow-growing tumors, tumors with no significant signs and symptoms, elderly patients, individuals where treatment, such as surgery, may be too risky, and individuals, who do not prefer surgical treatment for a variety of reasons (opting out of surgery through personal preference)
  • This approach may not be advised in individuals where the tumor develops in the background of an underlying genetic condition such as neurofibromatosis
  • Recurring brain scans may be taken to observe the rate of tumor growth; if the tumor is small and growing slowly, then there may be no need for invasive procedures
• Symptomatic treatment may involve the use of antiseizure medications, painkillers, steroids (to reduce inflammation), and administration of anti-depressants

Surgical treatment: Surgery to remove the entire tumor or just part of the tumor depends on several factors including the risk assessment by a neurosurgeon, with respect to the potential injury to nearby brain tissues. It is also considered based on the location, size, and overall health of the individual. A complete removal of the tumor can result in a cure in many patients. 

• Craniotomy: It is a surgical procedure wherein a tiny hole is created in the cranium to access and remove the tumor. The main goal of surgery is to remove as much tumor as possible without damaging the surrounding brain tissue
• In some individuals, the tumor is partially removed, so as not to cause brain damage, resulting in unwanted additional symptoms. A partial removal of tumor is usually considered in slow-growing grade I benign tumors
• Microsurgery: The surgery is performed using microsurgical techniques, which can help minimize damage to the accompanying nerve. Since the tumor mostly affects the covering around the nerves, it can be completely removed without affecting the nerve in most cases. The following techniques may be employed:
  • Subtotal removal; when the tumor is incompletely removed
  • Near total removal; when most of the tumor is removed and there is very little tumor remnants
  • Total tumor removal; when the tumor is removed completely
• In some cases, embolization of the tumor may be performed, in order to shrink the tumor size, before major invasive procedures are undertaken. In embolization, the blood supply to the tumor is cut-off, resulting in its shrinkage. This also helps reduce blood loss during a surgical resection
• Osteoplastic laminotomy: It is a minimally-invasive procedure to treat spinal cord tumors. The technique also helps minimize post-operative complications and provides increased spinal stability. If necessary, osteoplastic laminotomy may be followed up by a spinal column reconstruction procedure
• Laminectomy: An invasive procedure that is performed to relieve compression on the spinal cord or spinal nerves, caused by the tumors, by widening the spinal canal through removal of the laminae (part of the vertebra)
• Radiosurgery for individuals who cannot undergo surgery or have recurrent tumors
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals

Surgical procedures to remove brain tumors carry risks, including infection, possible damage to healthy brain tissue, swelling, or possible fluid build-up in the brain.

Radiation therapy: There are a variety of radiation therapy methods that can be used to treat the tumors. Radiation therapy is performed either after removal of the tumor (to destroy any remaining meningioma cells), or in individuals where surgical removal procedure is not an option. Radiation therapy is helpful to reduce the rate of recurrence. It is also recommended for individuals where the tumor is removed partially.

The types of radiation therapy include:

• Standard external radiation beam therapy using a beam of high-energy X-rays; it is the most common form of radiation therapy used to treat cancers
• 3-dimensional conformal radiation therapy, where 3-d images of the tumor are created using radiological imaging scans to help design appropriate radiation therapy beam size and angles
• Intensity modulated radiotherapy (IMRT): It is a procedure that uses computer-controlled linear accelerators to deliver precise radiation to a malignant tumor
• Stereotactic radiosurgery using Gamma Knife or CyberKnife technique
• Proton radiation therapy: It is a form of external beam therapy using high-energy proton beams to destroy the tumor cells
• Fractionated radiation therapy: It is a good option for individuals whose tumors are too large for radiosurgery, or if the tumor is in a sensitive location. In this therapy, small doses of radiation are administered for a certain set period

Some individuals may experience a few side effects, while others may experience none. These may include fatigue, headaches, hair loss, and scalp irritation. Radiation therapy beams may affect the pituitary gland causing it to dysfunction (bringing about hormonal changes in the body).

Chemotherapy: A large number of meningiomas (especially those classified as benign tumors) usually do not respond to chemotherapy. Hence, chemotherapy is not recommended as a treatment option for treating these tumors. However, the healthcare provider will determine if chemotherapy should be considered as a treatment option on a case-by-case basis.

• Chemotherapy may be beneficial in individuals diagnosed with atypical and malignant tumors. Whether to use chemotherapy as a treatment modality is determined by healthcare provider on case-by-case basis
• Chemotherapy for those tumors that are atypical and/or cannot be effectively treated by surgery or radiation therapy. The administration of some drugs may slow the rate of growth of the tumor

The following chemotherapy agents and methods have been used in atypical and malignant tumors with varying beneficial results:

• Immunotherapy to stimulate an affected individual’s immune system
• Somatostatin analogs which prevent the release of growth hormones
• Hydroxyurea, epidermal growth factor receptor inhibitors, platelet-derived growth factor receptor inhibitors, and vascular endothelial growth factor inhibitors

There are side effects for chemotherapy, which depends upon the type and dose of drugs administered. The common chemotherapy side effects include nausea, vomiting, hair loss, loss of appetite, headache, fever, chills, and weakness.

Clinical trials: In certain tumors with advanced stages of tumor progression, there may be some newer treatment options, currently on clinical trials, which can be considered for some patients depending on their respective risk factors.

Regular observation and periodic checkups to monitor the condition is strongly recommended following treatment. In order to avoid a relapse, or be prepared for a recurrence, the entire diagnosis, treatment process, drugs administered, healthcare recommendations post-treatment, etc. should be well-documented and follow-up measures initiated.

How can Meningothelial Meningioma be Prevented?

Presently, there are no specific methods or guidelines to prevent the formation of Meningothelial Meningioma. However, if it is associated with a genetic disorder, such as neurofibromatosis type 2 (NF2), the following points may be considered:

• Genetic counseling and testing: If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Regular health check-ups might help those individuals with a history of NF2 in the immediate family and help diagnose the tumor early

In general, the factors that can help reduce the incidence of meningioma and other brain tumor may include:

• Reducing exposure to radiation
• Avoiding cigarette smoke inhalation
• When feasible, it is recommended to decrease the frequency of oral X-rays
• Weight loss, in case one is obese or overweight; maintaining a good BMI
• Getting regular checkups following recovery from breast cancer or neurofibromatosis type 2
• Using safety gear including wearing helmets when playing sports or while riding two-wheelers
• Wearing seatbelts while driving automobiles to minimize the risk for head/body injury

According to the U.S. Preventive Services Task Force (USPSTF), currently there is no standard testing protocols available for meningioma.

Regular medical screening at periodic intervals with blood tests, scans, and physical examinations are mandatory. Often several years of active vigilance are crucial and necessary.

What is the Prognosis of Meningothelial Meningioma? (Outcomes/Resolutions)

The prognosis of Meningothelial Meningioma may vary considerably from one individual to another and is dependent on a set of factors. However, in many cases, the prognosis is good with adequate treatment, since it is a grade I benign tumor.

• Small tumors have better outcomes with adequate treatment generally, but this also depends on the location of the tumor. Tumors located near vital structures of the brain have poorer prognosis
• High morbidity and mortality locations include the cerebellopontine angle (CPA), petroclival junction, the sphenoid ridge and tuberculum sellae, and tumors involving the ventricular system and posterior parafalcine (falx) regions
• Benign tumors of spinal cord have better prognoses than benign tumors of the skull cavity; the 10-year survival rate for benign spinal meningioma is 96%, in comparison to intracranial benign meningioma which is at 83%
• Tumors that are slow-growing have better prognosis than rapidly-growing tumors. In general, the 10-year survival rate for benign meningioma is 84%

Specifically, the prognosis of Meningothelial Meningioma may depend upon the following factors:

• Tumor histology or grade of the tumor: The lower the grade, the better is the prognosis
• Age of the individual: Older individuals generally have poorer prognosis than younger individuals
• Extent of residual tumor in the body following a surgical resection: A complete surgical excision with entire tumor removal presents the best outcome. In some cases, large portions of the tumor may be removed; or, only a small portion for tissue biopsy
• Location of the tumor is an important prognostic factor: Tumors at certain sites involving the central nervous system are more difficult to surgically excise and remove. They can also cause considerable neurological damage at certain sites in the brain and/or spinal cord
• Functional neurologic status based on neurological evaluation of the patient: A higher score on the Karnofsky Performance Scale indicates a more favorable outcome

In general, the prognosis of a benign brain tumor may depend upon several factors, which include: 

• Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy
• Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
• The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
• Presence of certain genetic abnormalities
• Histological subtype of the tumor
• Individuals with bulky disease may have a poorer prognosis
• Involvement of other vital organs may complicate the condition
• The ease of accessibility and surgical resectability of the tumor (meaning, if the primary tumor can be removed completely). This is an important prognostic factor
• Whether the tumor is occurring for the first time or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur 
• Response to treatment and absence of post-operative complications: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
• Progression of the condition makes the outcome worse

An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Meningothelial Meningioma:

Please visit our Cancer & Benign Tumor Health Center for more physician-approved health information:

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